.--••   .-  .      •  .-  •••  Ej   ••'•:•     -  , 

'     -,-.      '       '  :  '-.;:,-   '•••• 
•  '  -  '  • 


WORKS    OF    ALLEN    HAZEN 

PUBLISHED    BY 

JOHN  WILEY  &  SONS,  INC. 


The  Filtration  of  Public  Water-Supplies. 

Third  Edition,  Revised  and  Enlarged.  8vo,  xii 
+  321  pages,  fully  illustrated  with  line  and  half- 
tone cuts.  Cloth,  $3.00. 

Clean  Water  and  How  To  Get  It. 

Second  Edition,  Revised  and  Enlarged.  Large 
12mo,  xii +  196  pages,  containing '18  full-page 
half-tone  illustrations.  Cloth,  $1.50. 

The  American  Civil  Engineers'  Pocket  Book. 

(Author  of  Section  on  Water  Supply,  Sewerage.  Irrigation) 
16mo.      Morocco,  $5.00  net. 


By  WILLIAMS  and  HAZEN 

Hydraulic  Tables. 

Showing  the  Loss  of  Head  due  to  the  Friction 
of  Water  Flowing  in  Pipes,  Aqueducts,  Sewers, 
etc. ,  and  the  Disc  harge  over  Weirs.  By  Gardner 
8.  Williams,  M.  Am.  Soc.  C.  E.,  of  Michigan, 
and  Allen  Hazen,  M.  Am.  Soc.  C.  E.  8vo,  iii  + 
75  pages.  Cloth,  $1.50. 


Interior  of  covered  pure-water  reservoir  at  Washington,  D.  C.f 
before  being  filled  with  water.  It  is  covered  for  the  purpose  of 
keeping  the  filtered  water  clean. 

Frontispiece 


CLEAN  WATER 

AND 

HOW  TO  GET  IT 


BY 

ALLEN    HAZEN 

MEMBER  OF  THE  AMERICAN  SOCIETY  OF  CIVIL  ENGINEERS,  THE  BOSTON 
SOCIETY    OF    CIVIL    ENGINEERS,  THE  AMERICAN  WATER  WORKS 
ASSOCIATION,  THE  NEW  ENGLAND  WATER  WORKS  ASSOCIA- 
TION, THE  AMERICAN  PUBLIC  HEALTH  ASSOCIATION, 
THE  SOCIETY  OF  ARTS,  ETC. 


SECOND  EDITION,   REVISED  AND  ENLARGED 
FIRST   THOUSAND 


NEW  YORK 

JOHN  WILEY  &  SONS,  INC. 

LONDON:   CHAPMAN  &  HALL:   LIMITED 

1914 


\ 


x 


Copyright,  1907,  1914, 
Bv  ALLEN  HAZEN. 


• 

.         r       •        *»      . 
•  »  ,*     «       . 


THE  SCIENTIFIC  PRESS 

ROBERT  DRUMMOND    AND  COMPANY 

BROOKLYN,  N.   Y. 


TO 

THE   BRISBANE   BOARD   OF  WATERWORKS 

IN  WHOSE  SERVICE  WAS   MADE 

THE    VOYAGE    ON    WHICH    THESE    PAGES 

WERE   WRITTEN 


287919 


PREFACE. 


THIS  little  volume,  originally  written  in  the  spare  hours 
of  a  long  ocean  voyage,  deals  with  the  means  now  used 
by  American  cities  to  secure  clean  water. 

Some  closely  allied  subjects  are  also  touched  upon, 
including  some  matters  of  general  policy,  pressure,  fire 
service,  the  sale  of  water,  and  the  financial  management 
of  water  works.  This  is  because  an  understanding  of 
these  matters  is  often  necessary  to  enable  the  means  of 
securing  a  new  supply,  or  improving  an  old  one,  to  be 
fully  considered. 

Matter  descriptive  of  existing  works  and  their  man- 
agement is  frequently  used  where  principles  can  best 
be  shown  by  it;  but  it  is  the  object  to  illustrate  principles 
and  not  to  describe  the  works  that  are  mentioned. 

Its  object  is  to  help  beginners  to  understand  some- 
thing of  the  first  principles. 

In  the  present  edition  chapters  have  been  added  upon 
the  red-water  trouble  and  upon  the  disinfection  of  water 
supplies,  in  the  knowledge  of  which  great  advance  has 
been  made  since  the  first  edition. 

The  statistics  have  also  been  brought  up  to  the  census 
of  1910,  and  corrections  and  additions  made  throughout 
the  volume. 


CONTENTS. 

CHAPTER  I. 
IMPOUNDING  RESERVOIR  SUPPLIES 


CHAPTER  II. 
WATER  SUPPLIES  FROM  SMALL  LAKES 26 

CHAPTER  III. 
SUPPLIES  FROM  THE  GREAT  LAKES 29 

CHAPTER  IV. 
WATER  SUPPLY  FROM  RIVERS 32 

CHAPTER  V. 
GROUND  WATER  SUPPLIES 42 

CHAPTER  VI. 

ON  THE   ACTION   OF   WATER  ON  IRON  PIPES  AND  THE  EFFECT 

THEREOF  ON  THE  QUALITY  OF  THE  WATER 59 

CHAPTER  VII. 

RED-WATER  TROUBLES 67 

vii 


Vlll  CONTENTS. 

CHAPTER  VIII. 

PAGE 

DEVELOPMENT  OF  WATER  PURIFICATION  IN  AMERICA 73 

CHAPTER  IX. 
ON  THE  NATURE  OF  THE  METHODS  OF  PURIFYING  WATER 89 

CHAPTER  X. 
DISINFECTION 100 

CHAPTER  XI. 

ON  THE  APPLICATION  OF  THE  METHODS  OF  WATER  PURIFICA- 
TION, ARRANGED  ACCORDING  TO  THE  MATTERS  TO  BE  RE- 
MOVED BY  THE  TREATMENT 109 

CHAPTER  XII. 
STORAGE  OF  FILTERED  WATER 132 

CHAPTER  XIII. 

ON  THE  REQUIRED  SIZES    OF    FILTERS    AND  OTHER  PARTS  OF 

WATER  WORKS 134 

CHAPTER   XIV. 

As  TO  THE  PRESSURE  UNDER  WHICH  WATER  is  TO  BE  DE- 
LIVERED    141 

CHAPTER  XV. 

ON  THE  USE  AND  MEASUREMENT  OF  WATER 151 


CONTENTS.  ix 

CHAPTER  XVI. 

PAGE 

SOME  FINANCIAL  ASPECTS 167 

CHAPTER  XVII. 
THE  LAYING  OUT  AND  CONSTRUCTION  OF  WORKS 175 

CHAPTER  XVIII. 

ON  THE  FINANCIAL  MANAGEMENT  OF  PUBLICLY  OWNED  WATER 
WORKS  . .         181 


LIST    OF    ILLUSTRATIONS. 


FACING   PAGB 

Interior  of  Covered  Pure-water  Reservoir  at  Washington, 

D.  C.,  before  being  filled  with  water.    It  is  covered  for 

the  purpose  of  keeping  the  filtered  water  dean. .Frontispiece 

The  Old   Croton  Darn.     This  view  was  taken  before  the 

filling  of  the  New  Croton  Dam,  which  now  entirely 

submerges  the  old  dam 2 

New  Croton  Dam.     Lower  down  the  stream  and  now  com- 
pletely submerging  the  old  dam 2 

One  of  the  Boston  Pumping  Stations "6 

Wachusett   Dam  of    the   Metropolitan  Water  Works  for 

Boston  and  Suburbs 6 

High  Bridge  in  1907.    Built  about   1840  to  carry  Croton 

water  across  the  Harlem  River  to  New  York  City ....       8 
Lake  Cheesman  Dam  and  Reservoir.     Denver  Union  Water 

Company 8 

Tubercles  Growing  in  Iron  Water-pipes 60 

Interior  of  a  Sand  Filter  at  Toronto,  showing  layer  of  dirty 

sand  removed  by  scraping 76 

Interior  of  covered  Pure-water  Reservoir  at  Watertown, 

N.  Y 76 

An  Early  Type  of  Mechanical  Filter  at  Chattanooga,  Tenn.      78 
The  Little  Falls  Filters  of  the  East  Jersey  Water  Company      78 

Coagulating  Devices  at  Watertown,  N.  Y 82 

Covered  Coagulating  Basins  and  Mechanical  Filters  in  Course 

of  Construction  at  Watertown,  N.  Y 82 

Interior  of  Filter  House.     Little  Falls  Filters  of  the  East 
Jersey  Water  Company,  showing  operating  table  for 

mechanical  niters 94 

xi 


Xil  LIST   OF  ILLUSTRATIONS. 

FACING  PAGE 

Bottom  of  a  Mechanical  Filter  at  Watertown,  N.  Y.,  with 
the  sand  removed  to  show  the  water  and  air  piping 
and  strainers 94 

Coagulation  and  Sedimentation  Basin  with  Aeration  of 
Entering  Water  and  with  Thorough  Baffling  to  Assist 
Sedimentation.  South  Pittsburgh  Filters 96 

Coagulating  andSedimentationBasin  with  Baffles  andPump- 

ing  Station  and  Filter  House  at  St.  Joseph,  Missouri .  96 

Aeration  of  Hemlock  Lake  Water  at  Rochester,  N.  Y.,  re- 
sulting in  a  reduction  of  tastes  and  odors 98 

An  Efficient  Aerator.  Temporary  Bronx  Supply,  New  York 

City 98 

Coagulant  House,  Washington  Filters,  where  chemicals  are 

mixed  and  applied  to  the  water  before  nitration 102 

Measuring-tanks  for  Controlling  the  Application  of  Hypo- 

chlorite  of  Lime  to  Filter  Effluents,  Yonkers,  N.  Y . . .  102 

Aeration  of  Missouri  River  Water  in  Passing  from  one  Set- 
tling Basin  to  another  at  Omaha,  Neb no 

Aeration  of  Water  in  Falling  over  a  Stone  Dam no 

Intermittent  Filters  at  Springfield,  Mass.,  showing  one  filter 

out  of  use  and  being  cleaned 112 

Intermittent  Filters  at  Springfield,  Mass.,  showing  aeration 
of  water  at  entrance  and  the  distribution  of  the  water 
to  the  four  filters 112 

The  New  Croton  Dam  Holding  back  Water  for  the  Supply 

of  New  York  City 116 

Interior  of  Mechanical  Filter  Plant,  Minneapolis 124 

Softening  Plant  for  Reservoir  Water  at  Oberlin,  Ohio 124 

General  View  of  Washington  Filters.  The  filters  are  cov- 
ered and  the  top  is  grassed  over  and  used  as  park.. .  126 

Interior  View  of  a  Filter  at  Washington,  showing  the 

hydraulic  removal  of  the  surface  layer  of  dirty  sand.  126 

Hydraulic  Washing  of  Dirty  Sand  from  Sand  Filters,  Wash- 
ington, D.  C.  (Original  design.) 130 

Sand  Washer  and  'Sand  Bins,  Washington  Filters.  (Im- 
proved design.) 130 


CLEAN  WATER  AND  HOW 
TO  GET  IT. 


CHAPTER  L 
IMPOUNDING    RESERVOIR    SUPPLIES. 

Croton  Works  of  the  City  of  New  York.  In  the  year 
1842,  when  New  York  City  had  a  population  of  about 
355,000,  Croton  water  was  first  brought  to  the  city.  It 
had  taken  seven  years  to  build  the  works.  The  water 
was  taken  from  the  Croton  River  through  an  aqueduct 
41  miles  long  to  the  city.  This  aqueduct  was  8  feet  5} 
inches  high,  7  feet  5  inches  wide,  had  a  slope  of  12.6 
inches  per  mile,  and  was  capable  of  carrying  95,000,000 
gallons  of  water  per  day.  This  aqueduct  crossed  the 
Harlem  River  which  separates  Manhattan  Island  on 
which  the  city  stands  from  the  mainland  on  a  masonry 
arched  bridge,  called  High  Bridge,  which  to-day,  sixty- 
five  years  afterward,  is  one  of  the  most  notable  of  the 
engineering  works  of  the  metropolis. 

In  the  city  were  built  reservoirs  to  receive  and  hold 
the  water,  and  from  them  it  was  piped  through  the  streets. 

Afterwards,  in  1890,  a  much  larger  aqueduct  was  put 
in  service,  capable  of  bringing  300,000,000  gallons  of 
water  per  day  from  the  Croton  River. 

A  dam  was  built  across  the  Croton  River  at  the  point 

i 


2  IMPOUNDING  RESERVOIR  SUPPLIES. 

of  intake,  raising  the  water  some  40  feet,  or  26  feet  above 
the  top  of  the  aqueduct.  The  use  of  this  dam  was  prin- 
cipally to  raise  the  water  to  the  required  elevation;  but 
it  also  served  to  a  slight  extent  to  hold  back  and  store 
water  when  an  excess  was  flowing  in  the  river  and  make 
it  available  when  there  would  not  otherwise  have  been 
enough. 

When  the  Croton  works  were  built  the  city  used 
12,000,000  gallons  of  water  per  day,  and  the  natural 
flow  of  the  river  was  sufficient.  The  Croton  River  is  a 
relatively  small  stream.  Above  the  intake  it  drains  an 
area  of  360  square  miles.  This  is  equal  to  a  square  with 
sides  of  19  miles  each. 

The  area  from  which  water  is  taken  to  supply  a  city 
is  called  in  England  a  catchment  area,  and  commonly  in 
the  United  States  a  watershed.  The  English  term  is 
more  accurate  and  better. 

In  dry  weather  the  flow  of  the  Croton  River  was  not 
very  large,  and  as  the  city  grew  and  needed  more  water 
it  soon  happened  that  there  were  times  when  there  was 
not  enough. 

The  city  then  began  to  build  storage  or  impounding 
reservoirs.  Dams  were  built  across  various  tributaries  of 
the  Croton  River,  forming  artificial  lakes  behind  them. 
The  larger  of  these  dams  were  of  solid  masonry.  The 
smaller  ones  were  often  built  more  cheaply,  and  just  as 
well,  of  earthen  embankments.  These  reservoirs  filled 
when  the  streams  were  in  flood,  and  the  water  was  let 
out  in  dry  times  as  it  was  needed. 

These  reservoirs  were  not  connected  by  pipes  or  aque- 
ducts with  the  city.  When  water  from  them  was  wanted 


The  Old  Croton  Dam.     This  view  was  taken  before  the  filling  of  the 

New  Croton  Dam,  which  now  entirely  submerges  the  old  dam. 
*  Courtesy  of  W.  H.  Sears,  Chief  Engineer  Board  of  Aqueduct  Commissioners,, 


New  Croton  Dam. 


Lower  down  the  stream  and  now  completely 
submerging  the  old  dam. 


CROTON  WORKS  OF  CITY  OF  NEW  YORK.   3 

the  gates  on  their  outlets  were  opened,  and  the  desired 
quantity  of  water  was  allowed  to  flow  down  the  natural 
channels  until  it  came  to  Croton  Lake,  as  the  reservoir 
formed  by  the  dam  first  built  was  called. 

Since  then  impounding  reservoirs  have  been  added  to 
the  Croton  system,  one  by  one,  as  the  needs  of  the  city 
have  grown.  The  system  is  now  complete,  and  it  will 
not  pay  to  add  others  because  those  now  available  hold 
all  the  flood  waters  that  can  be  practically  utilized  from 
the  catchment  area,  and  more  reservoirs  would  not  add 
to  the  supply. 

The  amount  of  water  that  can  be  utilized  may  be  stated 
in  this  way:  On  an  average  46  inches  of  rain  fall  each 
year  upon  the  catchment  area.  Of  this,  one-half  is  lost 
by  evaporation  from  the  water  surfaces,  from  the  sur- 
face of  the  ground,  and  especially  from  the  leaves  of  all 
the  plants  and  trees  that  grow  upon  it.  The  other  half, 
equal  to  a  rainfall  of  23  inches,  flows  off  in  the  streams 
and  sooner  or  later  reaches  Croton  Lake. 

In  wet  years  the  amount  that  flows  off  is  greater,  in 
dry  years  it  is  less,  than  the  average.  In  the  winter  and 
spring  months  the  flow  is  very  much  greater  than  at 
other  times. 

Now,  the  principal  use  of  the  impounding  reservoirs 
is  to  hold  the  excess  water  of  the  winter  and  spring 
flows  and  make  it  available  during  the  summer  and  fall. 

They  also  serve  to  a  less  extent  to  hold  the  water  of 
wet  years  and  to  make  it  available  in  dry  years. 

The  reservoirs  all  together  hold  an  amount  of  water 
equal  to  a  rainfall  or  runoff  of  about  18  inches  upon  the 
entire  catchment  area,  and  it  is  computed  that  the 


4  IMPOUNDING  RESERVOIR  SUPPLIES. 

amount  of  water  that  can  be  continuously  drawn  from 
the  system  by  the  aid  of  this  storage  through  a  dry  time 
is  17.5  inches  per  annum.  This  is  equal  to  an  average 
flow  of  300,000,000  gallons  per  day. 

The  whole  average  amount  of  water  running  off,  as 
measured  through  a  long  term  of  years,  amounts  to 
about  23  inches,  or  395,000,000  gallons  per  day,  but 
practically  that  part  of  this  amount  above  the  300,000,000 
gallons  daily  actually  utilized  cannot  be  made  available. 

To  do  it  would  require  reservoirs  of  extraordinary  size 
to  hold  the  excess  from  a  series  of  wet  years  and  make  it 
available  in  a  series  of  dry  years. 

These  reservoirs  would  cost  too  much  in  proportion  to 
the  added  quantity  of  water  obtained.  Further,  the 
gain  would  not  all  be  utilized,  first,  because  with  added 
water  surface  thero  would  be  more  loss -by  evaporation; 
and,  second,  because  there  would  be  a  deterioration  in 
the  quality  of  the  water  on  holding  it  so  long  in  reservoirs 
which  would  be  sometimes  full  and  sometimes  empty. 

Catskill  Supply  for  New  York.  A  new  source  of  supply 
for  New  York  City  to  supplement  the  Croton  supply  has 
been  authorized  and  is  now  under  construction.  The 
catchment  area  is  in  the  Catskill  mountains,  nearly  a 
hundred  miles  as  the  water  flows  from  New  York  City 

The  part  of  the  catchment  area  first  developed  is  that 
of  Esopus  Creek.  This  has  an  area  of  255  square  miles. 
It  is  thus  considerably  smaller  than  the  Croton  catch- 
ment area.  It  is  the  plan,  however,  to  divert  several 
neighboring  areas  when  they  are  needed,  and  all  the 
works  are  built  with  reference  to  this  end. 

In  one  respect  the  development  is  quite  different  from 


BOSTON  SUPPLIES.  5 

that  of  the  Croton.  Instead  of  providing  a  series  of 
relatively  small  reservoirs,  added  from  time  to  time  as 
the  needs  of  the  city  require,  the  whole  ultimate  storage 
will  be  provided  by  one  enormous  reservoir,  called  the 
Ashokan  Reservoir.  This  will  hold  132,000,000,000 
gallons  of  water,  and  will  be  the  largest  artificial  reser- 
voir for  water  supply  in  America,  if  not  in  the  world. 

This  reservoir  is  much  larger  than  it  would  pay  to 
build  for  the  Esopus  catchment  area  alone.  It  is  built 
so  large  in  order  that  it  may  also  serve  to  store  water 
from  the  other  catchment  areas  which  are  to  be  later 
diverted  to  it.  It  also  differs  from  the  Croton  develop- 
ment in  the  manner  of  drawing  the  water.  All  the 
storage  is  in  one  reservoir,  and  the  aqueduct  to  the 
city  leads  directly  from  it,  so  that  the  flow  through 
the  natural  channel  from  the  upper  reservoirs  to  the 
lower  one  on  the  Croton  has  no  equivalent  in  the  Esopus 
plan. 

Boston  Supplies.  Boston  is  also  supplied  with  water 
from  impounding  reservoirs  upon  relatively  small  streams. 
The  first  of  these  reservoirs  was  Lake  Cochituate,  a 
natural  lake  taken  for  the  purpose  of  a  reservoir,  and 
since  then  treated  precisely  as  an  artificial  reservoir 
would  have  been  treated. 

Cochituate  water  first  entered  Boston  in  1848,  when 
the  city  had  a  population  of  128,000,  and  the  capacity  of 
the  works  first  built  was  9,000,000  -gallons  per  day. 

The  Mystic  works,  also  making  use  of  a  natural  lake 
as  a  reservoir,  were  abandoned  in  1898,  because  of  the 
great  increase  in  population  upon  the  catchment  area, 
which  was  very  near  to  the  city. 


6  IMPOUNDING  RESERVOIR  SUPPLIES. 

The  Sudbury  River  water  first  came  to  Boston  in 
1878,  as  an  addition  to  the  Cochituate  supply.  The 
catchment  area  of  this  river  was  gradually  developed  by 
a  series  of  seven  comparatively  small  reservoirs,  added 
from  time  to  time  in  the  same  way  that  those  upon  the 
Croton  catchment  area  were  added  as  needed. 

The  Sudbury  supply  becoming  inadequate,  a  further 
large  addition  was  made  in  the  Wachusett  Reservoir, 
upon  the  south  branch  of  the  Nashua  River.  The 
Wachusett  water  first  entered  Boston  in  1898.  As  in 
the  case  of  the  new  supply  for  New  York,  all  the  storage 
is  in  one  great  reservoir,  the  Wachusett  Reservoir,  hold- 
ing 63,000,000,000  gallons  of  water.  When  first  built 
it  was  the  largest  artificial  reservoir  in  existence.  It 
was  cheaper  to  build  one  large  reservoir  than  a  series  of 
smaller  ones  of  the  same  total  capacity;  and  as  the 
resources  and  growth  of  the  city  justified  a  complete 
development  in  this  respect  at  the  outset,  it  was  clearly 
best  to  do  it  in  this  way. 

Other  Impounding  Reservoir  Supplies.  Baltimore  is 
supplied  from  impounding  reservoirs  upon  the  Gunpow- 
der River,  and  many  large  and  small  cities  in  the  Eastern 
states  are  similarly  supplied.  Among  them  are  Newark 
and  Jersey  City,  New  Jersey;  Worcester,  Cambridge, 
and  Springfield,  Massachusetts;  New  Haven  and  Hart- 
ford, Connecticut;  Altoona,  Pennsylvania,  and  many 
others. 

Reservoirs  only  Partially  Connected  with  their  Catch- 
ment Areas.  Many  impounding  reservoirs  have  been 
built  larger  than  could  be  filled  from  the  catchment  areas 
naturally  tributary  to  them,  and  additional  areas  have 


One  of  the  Boston  Pumping  Stations. 


Wachusett  Dam  of  the  Metropolitan  Water  Works  for  Boston 

and  Suburbs. 
Courtesy  of  Dexter  Brackett,  Chief  Engineer  Metropolitan  Water  Board. 


IMPOUNDING  RESERVOIRS  WITH  PUMPING.        7 

been  made  partially  tributary  to  them  to  insure  their 
being  filled.  At  Hartford,  Conn.,  for  example,  side-hill 
or  contour  ditches  are  used  to  considerably  extend  the 
natural  catchment  areas. 

It  only  occasionally  happens  that  the  channels  pro- 
vided in  such  cases  are  large  enough  to  carry  the  largest 
flood  flows  or  tight  enough  to  hold  all  the  dry  weather 
flows.  Usually,  therefore,  more  or  less  water  is  lost  in 
such  connections,  and  the  quantity  of  water  available  is 
correspondingly  less. 

At  Lynn,  Mass.,  an  additional  area  is  made  available 
by  means  of  pumps  which  lift  water  when  the  natural 
flow  is  sufficient  from  the  Saugus  River  to  a  reservoir  too 
large  to  be  filled  from  its  own  catchment  area.  The 
Staines  reservoirs  for  London,  England,  operate  in  the 
same  way;  that  is  to  say,  the  flood  flows  of  the  Thames 
are  pumped  to  them,  to  be  let  out  again  when  there  is 
need  of  the  water. 

Impounding  Reservoirs  with  Pumping.  By  far  the 
greater  number  of  impounding  reservoirs  are  elevated 
above  the  cities  which  they  serve,  and  water  flows  from 
them  by  gravity  to  the  places  where  it  is  to  be  used.  But 
there  are  cases  where  the  reservoirs  are  not  high  enough 
to  allow  this  to  be  done.  This  is  particularly  the  case 
along  the  sea-coast,  and  in  general  where  the  ground  is 
comparatively  flat  and  the  catchment  areas  but  little 
elevated  above  the  cities  which  they  serve. 

Gloucester  and  Lynn,  Mass.,  pump  all  their  water 
from  impounding  reservoirs  located  but  little  above  tide- 
level,  and  similar  arrangements  are  in  use  at  Charleston, 
S.  C.,  Norfolk,  Va.,  etc. 


8  IMPOUNDING  RESERVOIR  SUPPLIES. 

Columbus,  Ohio,  should  be  mentioned  in  this  connec- 
tion. The  Scioto  River,  with  a  catchment  area  of  1032 
square  miles  above  the  water  works'  intake,  usually,  sup- 
plies all  the  water  that  is  needed.  But  in  dry  times  there 
is  not  enough  water  naturally  flowing  in  the  river.  The 
city  has  built  a  masonry  dam  46  feet  high,  holding  in 
reserve  1,627,000,000  gallons  of  water  to  help  maintain 
the  supply  during  dry  times,  with  provision  for  increasing 
the  reservoir  when  the  growth  of  the  city  requires  it. 
The  Columbus  supply,  while  in  most  respects  to  be 
classed  as  a  river  supply,  comes  to  a  certain  extent  within 
the  class  of  impounding  reservoirs  which  require  pump- 
ing. 

Impounding  Reservoirs  in  the  West.  Denver  is  sup- 
plied in  part  with  water  from  an  impounding  reservoir 
upon  the  South  Platte  River.  The  dam  is  of  stone 
masonry,  with  a  maximum  height  of  235  feet,  and  holds 
24,000,000,000  gallons  of  water. 

San  Francisco  and  Oakland  are  also  supplied  from 
large  impounding  reservoirs.  Two  or  three  years'  sup- 
ply are  held  in  reserve  in  these  cases.  This  is  a  far 
larger  allowance  than  is  provided  in  most  Eastern  cities 
where  the  reserve  rarely  reaches  a  year's  supply,  and 
sometimes  is  only  sufficient  to  last  for  a  month  or  two. 

The  reason  for  the  very  great  amount  of  storage  needed 
at  San  Francisco  is  to  be  found  in  the  great  inequality 
of  the  rainfall.  There  are  often  years,  and  sometimes 
two  years  in  succession,  when  the  natural  runoff  is  not 
large  enough  to  maintain  the  supply.  Reservoirs  must 
therefore  be  provided  to  fill  in  the  year  when  there  is  rain, 
and  to  maintain  the  supply  when  there  is  but  little  rain; 


High   Bridge  in   1907.     Built  about    1840  to    carry  Croton  wator 
across  the  Harlem  River  to  New  York  Citv. 


Lake  Cheesman  Dam  and  Reservoir.     Denver  Union  Water  Com- 
pany. 


"  "*,if  "^  t   •    *  e^-T  «•   *" 


COMPUTATION    OF    STORAGE    REQUIRED.          9 

and  experience  shows  a  reserve  for  a  period  of  three  years 
to  be  necessary. 

This  is  a  far  different  condition  from  that  of  the  East- 
ern states,  where  a  substantial  runoff  can  be  counted 
upon  every  winter. 

Computation  of  the  Amount  of  Storage  Required.  This 
must  be  based  upon  records  of  runoff  or  flow  of  the 
stream,  for  which  calculations  are  to  be  made,  covering 
a  series  of  years. 

In  case  such  records  are  not  obtainable,  as  is  often  the 
case,  an  estimate  may  be  based  on  calculations  resting 
upon  the  actual  records  of  streams  which  have  been 
measured  and  which  are  believed  to  be  similar  to  the  one 
under  consideration. 

Very  good  records  of  the  flow  of  the  Croton  River  are 
available.  There  are  also  good  records  of  the  Sudbury 
River.  Both  of  these  go  back  to  about  1870.  They  are 
particularly  valuable  because  there  were  some  very  dry 
years  about  1881-3,  and  these  records  cover  this  period. 
For  more  recent  years  there  are  more  available  records. 
The  runoff  from  the  Wachusett  catchment  area,  from 
the  Pequannock  catchment  area  of  the  City  of  Newark, 
and  some  others  have  been  measured. 

In  addition,  the  United  States  Geological  Survey  has 
measured  the  flows  of  many  streams  in  the  last  years. 
This  work  is  most  helpful,  though  unfortunately  an 
effort  has  been  made  to  do  more  work  than  the  means  at 
hand  would  permit  to  be  done  well,  and  many  of  the 
results  must  be  used  only  with  considerable  caution. 

Rainfall  records  are  easier  to  get  and  are  much  more 
generally  available  than  runoff  records.  They  are  of 


10  IMPOUNDING  RESERVOIR  SUPPLIES. 

some  help  in  comparing  different  streams,  and  especially 
in  comparing  a  given  dry  period  for  which  the  runoff 
has  been  observed  with  other  dry  periods  for  which 
there  are  no  runoff  records.  Even  in  such  cases  rainfall 
records  are  apt  to  be  misleading,  because  there  is  no 
close  relation  between  observed  rainfall  and  runoff.  In 
almost  every  long  continued  record  it  is  found  that  the 
year  of  least  rainfall  is  not  the  year  of  least  runoff. 

In  general  it  may  be  said  that  for  Southern  New  Eng- 
land, and  for  New  York,  south  of  the  Catskill  Moun- 
tains, and  for  Northern  New  Jersey  (and  this  is  the 
region  in  the  United  States  where  impounding  reservoirs 
have  been  most  extensively  used)  fairly  good  estimates 
of  the  amount  of  storage  required  to  maintain  a  given 
supply  from  a  given  catchment  area  may  be  made  by  a 
proper  application  of  the  published  figures  of  flow  from 
the  Croton,  Sudbury,  and  Wachusett  catchment  areas. 
Outside  of  this  region  the  data  for  computing  runoff, 
and  the  required  amount  of  storage  are  less  numerous 
and  less  exact,  and  the  accuracy  of  the  computation  must 
therefore  be  less,  even  when  made  by  the  best  qualified 
engineers. 

In  a  general  way,  within  the  limits  above  noted,  with  a 
storage  of  11.5  inches  of  runoff,  or  200,000,000  gallons 
of  water  per  square  mile  of  catchment  area,  a  yield  of 
16.8  inches,  or  800,000  gallons  per  day  per  square  mile 
may  be  counted  on,  and  one-half  this  quantity  of  water 
can  be  secured  with  one-fourth  this  amount  of  storage, 
as  shown  by  the  following  table.  Land  area  only  is 
counted  in  these  calculations,  that  part  of  the  catchment 
area  which  is  covered  with  water  being  excluded,  as  the 


CARE  OF  CATCHMENT  AREAS. 


II 


evaporation  from  it  nearly  equals  the  rainfall  in  a  dry 
year. 

STORAGE  REQUIRED  IN  GALLONS  PER  SQUARE  MILE  OF  LAND 
SURFACE  TO  PREVENT  A  DEFICIENCY  IN  THE  SEASON  OF 
GREATEST  DROUGHT  WHEN  THE  DAILY  CONSUMPTION  is 
AS  INDICATED. 


DAILY  YIELD. 

STORAGE  REQUIRED. 

Gallons  per  sq.  mile. 

Inches  per  annum. 

Gallons  per  sq.  mile. 

Inches  of  runoff  « 

2OO,OOO 

4.2 

10,000,000 

0.6 

300,000 
400,000 

8.'  4 

30,000,000 
50,000,000 

2.9 

5OO,OCO 
600,000 
700,000 
800,000 

10,5 

12.6 

14.7 

16.8 

75,000,000 

100,000,000 

140,000,000 

200,000,000 

4-3 
5-8 
8.1 

"•5 

It  must  be  remembered  that  even  within  the  limits  of 
area  mentioned  there  is  considerable  difference  in  yield- 
ing power  of  catchment  areas,  and  these  can  be  to  some 
extent  allowed  for  when  sufficient  data  are  at  hand. 

It  does  not  make  very  much  difference  in  case  of  par- 
tial development  whether  all  of  a  catchment  area  is 
tributary  to  the  reservoir  or  only  a  part  of  it,  provided 
that  the  reservoir,  and  every  reservoir,  if  there  are  more 
than  one,  must  have  catchment  area  back  of  it,  so  that 
the  least  winter  runoff,  which  may  be  taken  roughly  at 
12  inches,  will  completely  fill  it  after  it  is  empty. 

The  above  figures  apply  only  to  the  area  mentioned. 
In  other  parts  of  the  country  the  conditions  of  runoff  are 
widely  different. 

Care  of  Catchment  Areas.  The  catchment  areas  sup- 
plying impounding  reservoirs,  and  the  natural  ponds  and 
lakes  used  as  reservoirs,  are  limited  in  area,  when  com- 
pared, for  example,  with  the  catchment  areas  of  the 


12  IMPOUNDING  RESERVOIR  SUPPLIES. 

great  rivers  from  which  many  public  water  supplies  are 
drawn.  It  is,  therefore,  possible  to  inspect  them  in  a 
sanitary  way  and  to  keep  track  of  what  is  taking  place 
upon  them.  It  is  usual  for  cities  to  devote  some  atten- 
tion to  this  subject. 

The  ideal  catchment  area  is  free  from  human  habita- 
tion and  is  covered  with  forest.  Lynn,  Mass.,  and 
Hartford,  Conn.,  own  all  or  practically  all  of  the  catch- 
ment areas  of  some  of  their  reservoirs,  and  are  encour- 
aging forests  to  grow  upon  them.  It  has  not  been 
possible  to  extend  this  policy  to  all  catchment  areas. 
This  is  because  the  growth  of  the  cities  is  such  that  when 
a  certain  catchment  area  is  well  in  hand,  another  and 
larger  one  must  be  taken  to  maintain  the  supply,  and  a 
long  time  must  elapse  before  that  can  be  brought  to  the 
standard. 

It  is  often  impossible  to  remove  population  from  a 
catchment  area,  and,  in  fact,  it  is  usually  unnecessary  to 
do  so.  Very  good  water  is  drawn  from  areas  upon  which 
there  is  much  population,  when  proper  and  well  known 
precautions  are  taken.  There  are  775  people  per  square 
mile  upon  the  Cochituate  catchment  area,  292  upon  tbe 
Sudbury,  45  upon  the  Wachusett,  and  69  upon  the  Cro- 
ton,  yet  it  is  not  to  be  supposed  that  the  waters  drawn 
are  seriously  impaired  by  these  populations.  And  as 
better  means  of  handling  the  water  are  used,  the  influ- 
ence of  population  upon  the  quality  of  the  water  becomes 
less. 

The  storage  of  water  in  large  reservoirs  tends  strongly 
to  improve  its  sanitary  quality.  Disease  germs,  if  they 
are  present,  die  in  water  in  such  storage.  In  our  climate, 


CARE  OF  CATCHMENT  AREAS.        1$ 

at  least,  they  never  grow  in  storage  reservoirs,  and,  if 
introduced,  the  length  of  time  that  they  can  live  is  lim- 
ited. This  is  practically  what  makes  the  Boston  water 
and  the  New  York  water  relatively  safe.  The  greatest 
danger  is  that  some  polluted  water  will  sometimes  get  by 
the  reservoir,  or  flow  through  it  by  some  short  cut,  and 
so  reach  the  consumers  before  it  has  been  subjected  to 
full  storage  conditions  for  a  sufficient  length  of  time. 

Further,  the  influence  of  the  population  upon  the  qual- 
ity of  the  water  in  the  future  will  be  less  than  it  now  is, 
because  it  now  seems  clear  that  in  order  to  improve  the 
physical  character  of  the  water,  as  will  be  explained  at 
length,  the  water  of  these  reservoirs  is  sure  to  be  sub- 
jected to  some  process  of  purification  before  delivery, 
and  when  this  is  done  such  effects  of  pollution  as  there 
may  be  will  largely  be  removed  at  the  same  time  and  by 
the  same  means. 

There  is  therefore  no  real  reason  for  attempting  to 
turn  back  into  their  primeval  forested  state  the  cultivated 
and  populated  areas  from  which  it  is  necessary  to  take 
the  water  to  supply  our  cities.  The  practice  of  Boston, 
New  York,  and  many  other  cities  is  sufficient,  and  this 
practice  may  be  briefly  stated  as  follows: 

There  is  a  sanitary  inspector  who  makes  himself 
familiar  with  the  whole  catchment  area.  Suitable  laws 
give  authority.  Manufacturing  wastes  and  human 
wastes  are  kept  out  of  the  main  streams  and  the  smaller 
tributaries  of  the  catchment  areas.  Where  expense  is 
involved  to  remove  old  sources  of  pollution,  the  city 
pays  it,  and  new  sources  of  pollution  are  not  permitted. 
The  city  owns  the  shores  of  the  reservoirs,  and  also 


14  IMPOUNDING  RESERVOIR  SUPPLIES. 

often  the  land  along  the  more  important  streams.  Some- 
times properties  that  are  especially  likely  to  pollute  the 
water,  as,  for  example,  old  mills  using  water  power,  are 
acquired  by  purchase  or  condemnation.  In  these  ways 
the  grosser  pollutions  are  kept  out  of  the  water  by  the 
city,  and  the  rural  population  upon  the  catchment  area 
remains  comparatively  undisturbed. 

The  purchase  of  all  unoccupied  lands  on  the  catch- 
ment areas,  which  can  be  bought  at  fair  prices,  is  often 
to  be  recommended,  but  it  has  not  often  been  carried 
out. 

The  development  of  manufacturing  and  suburban 
centers  upon  catchment  areas,  especially  where  there  is 
good  train  and  trolley  service,  and  other  favorable  con- 
ditions, is  more  to  be  feared.  Such  developments  will 
no  doubt  lead  ultimately  to  the  abandonment  of  some  of 
the  Boston  catchment  areas,  and  perhaps  at  a  later  date 
of  the  Croton,  and  some  others,  and  the  substitution  of 
other,  larger  and  more  remote  areas. 

But  the  possibilities  of  water  purification,  as  yet  but 
slightly  realized,  must  be  taken  into  account,  and  it  may 
be  a  long  time  before  this  happens. 

Stagnation  of  Water  in  Impounding  Reservoirs.  In 
our  climate,  when  a  reservoir  or  lake  is  more  than  from 
20  to  40  feet  deep,  the  upper  part  of  the  water  is  usually 
in  circulation  under  the  influence  of  the  wind,  and  the 
lower  part  remains  stagnant.  There  is  little  or  no 
mixing  between  the  surface  water  and  the  bottom 
water,  except  for  two  short  periods  each  year,  one 
in  the  spring  and  one  in  the  fall.  These  periods  of 
circulation  to  the  bottom  are  known  to  water  works 


STAGNATION  OF  WATER.  1$ 

men  respectively  as  the  spring  turnover  and  the  fall 
turnover. 

At  the  time  of  the  spring  turnover  all  the  water  mixes 
from  top  to  bottom  and  has  a  temperature  approximately 
that  at  which  water  has  its  greatest  density,  namely, 
39°  F.  Afterwards  the  sun  warms  the  surface  water 
above  this  temperature.  This  makes  it  lighter,  and  then 
it  will  not  go  down  again  to  mix  with  the  colder  and 
heavier  water  below,  but  remains  at  the  surface. 

The  wind  stirs  it  up  for  a  certain  depth.  This  depth 
is  about  20  feet  in  small  reservoirs  and  about  40  feet  in 
the  great  lakes.  In  this  surface  layer  the  temperature 
may  rise  in  midsummer  at  the  surface  to  75°  or  80°  or 
more. 

Below,  the  water  is  cooler,  and  some  distance  down 
it  rapidly  falls  to  the  temperature  of  the  whole  mass  of 
the  bottom  water.  And  this  bottom  layer  to  within  20 
or  40  feet  of  the  surface,  depending  upon  the  size  of  the 
reservoir,  remains  quiet  and  stagnant  and  unmixed  with 
the  surface  water  from  spring  until  fall.  Its  temperature 
gradually  and  slowly  increases,  but  it  is  always  cool  and 
still. 

In  the  fall  the  temperature  of  the  top  water  falls,  until 
it  approaches  that  of  the  bottom  water.  As  the  differ- 
ence is  less  the  wind  action  extends  deeper,  until,  all  at 
once,  often  when  the  wind  is  blowing,  all  the  water  in  the 
reservoir  turns  over  and  mixes  from  top  to  bottom.  The 
mixing  continues  for  a  few  weeks,  until  the  temperature 
of  the  surface  water  falls  below  the  point  of  maximum 
density.  Then  the  colder  water  commences  to  accumu- 
late at  the  top.  The  top  often  freezes  and  entirely  shuts 


16  IMPOUNDING  RESERVOIR  SUPPLIES. 

out  wind  action,  so  that  the  period  of  winter  stagnation 
is  even  more  quiet  than  the  summer  period.  It  is  ter- 
minated by  the  warming  of  the  surface  water  in  spring, 
until  it  reaches  the  temperature  of  the  bottom  water, 
when  the  spring  turnover  again  takes  place. 

Now,  this  phenomenon  of  stagnation  has  much  to  do 
with  the  quality  of  the  water. 

Without  attempting  to  go  into  the  chemistry  of  the 
processes,  the  most  important  conditions  are  these:  In 
the  brief  period  of  circulation  following  the  spring  turn- 
over, the  water  contains  normally  a  large  amount  of  oxy- 
gen or  air  in  solution,  as  does  almost  any  pure  natural 
surface  water0  And  when  the  period  of  summer  stag- 
nation sets  in,  the  bottom  water  is  well  charged  with  this 
oxygen.  Now,  on  the  sides  and  bottom  of  the  reservoir, 
in  contact  with  this  stagnant  water,  there  is  much  organic 
matter,  and  further  quantities  of  organic  matter  settle 
down  from  time  to  time  from  the  warmer  surface  water. 
These  are  in  the  form  of  the  dead  or  living  bodies  of 
organisms  that  have  grown  in  the  warm  surface  water 
in  the  sunshine  and  have  then  sunk  away  from  it  into  the 
cool  dead  water  below.  Now,  the  organic  matter  on  the 
bottom,  and  that  coming  down  from  above,  soon  start 
to  ferment  and  decompose  and  become  oxidized.  That 
is  to  say,  they  are  converted  back  into  their  constituent 
elements,  and  this  is  done  at  the  expense  of  the  oxygen 
held  in  solution  in  the  water.  This  oxygen  lasts  for  a 
time,  but  long  before  the  summer  is  over  it  is  all  used  up. 

In  the  absence  of  oxygen  (for  there  is  no  more  below, 

.  and  without  circulation  there  is  no  way  that  it  can  get 

down  from  above)  the  organic  matters  still  continue  to 


STAGNATION  OF  WATER.  17 

decompose,  but  they  decompose  in  another  way*  The 
decomposition  that  takes  place  in  the  absence  of  oxygen 
is  called  putrefaction.  Now  putrefaction  produces  some 
vile  odors  and  nasty  tastes.  It  is  largely  because  of 
these  odors  and  tastes  that  we  are  interested  in  it. 

These  odors  and  tastes  accumulate  in  the  bottom  water 
until  the  fall  turnover;  then  they  become  mixed  with 
all  the  water  in  the  reservoir.  And  if  the  water  is  drawn 
from  the  reservoir  near  the  top,  as  it  usually  is,  there  will 
be  a  great  change  in  the  quality  of  the  water  on  the  day 
of  the  fall  turnover. 

These  odors  and  tastes  will  make  an  impression  upon 
the  quality  of  the  water  at  other  times.  Reservoir  out- 
lets at  certain  levels  do  not  draw  water  from  those  levels 
only,  as  is  sometimes  supposed.  Instead,  they  draw 
somewhat  from  all  directions  where  there  is  water;  from 
above  and  from  below,  as  well  as  from  the  plane  of  their 
own  levels.  And  so,  in  the  natural  course  of  events,  even 
though  water  is  drawn  only  from  the  top,  some  bottom 
water  will  be  drawn  with  it,  and  the  odors  and  tastes  of 
putrefaction  will  be  carried  to  a  greater  or  less  extent 
with  it  into  the  supply,, 

The  odors  and  tastes  of  putrefaction  are  rapidly  dis- 
sipated and  destroyed  by  exposure  of  the  water  containing 
them  to  the  air.  But  to  effect  this  dispersion  the  expo- 
sure must  be  in  some  active  or  even  violent  way,  such  as 
playing  through  a  fountain,  or  falling  over  a  dam,  or 
flowing  in  a  rapid,  strong  current  down  the  natural  bed 
of  a  stream  with  a  rapid  fall. 

In  the  Croton  system  this  effect  of  aeration  to  disperse 
the  odors  and  tastes  of  putrefaction  is  used  to  a  large 


1 8  IMPOUNDING  RESERVOIR  SUPPLIES, 

extent.  Most  of  the  storage  reservoirs  are  high  in  ele- 
vation above  Croton  Lake.  When  water  from  them  is 
needed,  it  is  the  bottom  water  which  is  mainly  drawn. 
This  water,  often  foul  smelling  as  drawn,  rapidly  cleans 
itself  as  it  flows  through  the  outlet  fountains  and  over  the 
rocky  channels  to  the  lower  reservoir,  from  which  it 
flows  to  the  city.  The  old  Croton  Lake  was  too  small 
to  develop  putrefactive  action  on  its  own  account  to  an 
objectionable  extent,  and  so  the  city  was  substantially  free 
from  the  odors  and  tastes  resulting  from  putrefaction. 

The  new  Croton  dam,  making  a  reservoir  taking  the 
place  of  the  old  Croton  Lake,  but  vastly  larger,  has  not 
improved  conditions  in  this  respect.  The  results  of 
putrefaction  in  it  are  more  noticeable  in  the  city. 

Putrefaction  is  not  universal  in  stored  waters.  Many 
lakes  and  a  few  very  clean  reservoirs  are  free  from  it. 

Reservoirs  less  than  20  feet  deep  are  kept  in  circula- 
tion by  the  wind  to  the  bottom  all  summer,  and  in  general 
the  phenomenon  of  stagnation  and  putrefaction  do  not 
take  place  in  them.  In  many  cases,  however,  with  dirty 
bottoms  and  strong  growths  of  weeds  and  organisms, 
putrefaction  does  take  place  in  the  lower  part  of  even 
quite  shallow  reservoirs.  Unmistakable  evidences  of 
this,  for  example,  have  been  found  in  the  Ludlow  Reser- 
voir at  Springfield,  Mass.,  and  even  in  the  extremely 
shallow  Goose  Creek  Reservoir  at  Charleston,  S.  C. 

Odors  and  Tastes  from  Growths  of  Organisms.  Many 
kinds  of  organisms  grow  in  impounding  reservoirs,  rang- 
ing all  the  way  from  the  humblest  germ  to  the  full-grown 
fish  and  lily-pad.  Most  of  these  organisms  do  no 
particular  harm,  but  some  of  the  kinds  are  extremely 


ODORS  AND  TASTES.  19 

troublesome.  They  are  troublesome  principally  because 
of  the  odors  and  tastes  which  they  produce  in  the  water. 
Some  of  these  come  from  essential  oils  which  the  organ- 
isms produce  and  liberate  during  their  growth,  and  some 
of  them  result  from  the  death  and  decay  of  the  bodies  of 
the  organisms.  Some  of  the  troublesome  organisms  feed 
upon  other  organisms  or  their  remains.  These,  in  a  general 
way,  may  be  compared  to  the  higher  animals.  Some  of 
these  may  grow  and  become  troublesome  in  winter  under 
the  ice.  But  the  most  troublesome  organisms  are  the 
algae  and  other  microscopic  organisms  which  grow  in 
the  sunlight  near  the  surface  of  the  water. 

These  organisms  are  comparable  to  the  higher  plants. 
They  do  not  depend  upon  organic  matter  or  the  bodies 
of  other  organisms  for  their  food  supply.  They  require 
only  the  carbonic  acid  and  the  nitrogen  and  the  mineral 
matters  always  present  in  the  water  and  in  the  air,  and 
the  sunshine  for  their  growth.  And  from  these  simple 
materials  they  build  up  the  matters  which  compose  their 
bodies,  and  which  give  rise  to  the  odors  and  tastes,  just 
as  a  tree  builds  up  its  own  substance  from  the  mineral 
matter  of  the  soil  and  the  carbonic  acid  of  the  air,  with 
only  the  help  of  the  sunshine. 

Where  there  is  considerable  population  upon  the  catch- 
ment area  of  a  pond  or  reservoir,  the  pollution  reaching 
the  water  from  it  serves  as  a  food  supply  for  certain 
organisms  and  stimulates  their  growth  to  a  noticeable 
degree. 

There  are  many  kinds  of  algae,  and  they  differ  greatly 
in  their  odor-producing  powers.  Practically  all  Ameri- 
can impounding  reservoir  waters  suffer  from  them,  but 


20  IMPOUNDING  RESERVOIR  SUPPLIES. 

some  far  more  than  othersc  English  reservoirs  seem  to 
be  comparatively  free  from  them,  probably  because  of 
the  lower  temperatures  of  the  surface  waters.  English 
reservoir  surface  temperatures  do  not  often  stay  long 
above  60°  F.  and  seldom  go  above  65°.  American  reser- 
voirs have  temperatures  fully  10°  higher  in  summer,  and 
this  seems  to  be  the  most  important  point  of  difference. 

In  some  Australian  impounding  reservoirs,  very  high 
surface  summer  temperatures  are  obtained,  and  strong 
growths  take  place;  but  it  does  not  appear  that  the  odors 
and  tastes  produced  by  sub- tropical  conditions  in  Aus- 
tralia, and  in  the  southern  part  of  the  United  States,  are 
as  much  more  objectionable  when  compared  with  those 
in  the  climate  of  New  York,  as  might  be  reasonably  in- 
ferred from  the  very  great  increase  in  the  amount  of 
such  trouble  in  the  climate  of  New  York  as  compared 
with  English  conditions. 

Growths  often  do  not  occur  in  a  particular  reservoir 
supply  because  it  is  not  seeded,  but  there  is  no  known 
way  of  preventing  seeding. 

A  certain  degree  of  quiet  and  repose  is  necessary  for 
the  development  of  the  organisms.  This  is  why  they 
never  grow  in  rivers  and  flowing  water.  Wave  action 
from  wind  also  prevents  growth,  and  this  seems  to  be 
one  reason  why  large  lakes  and  reservoirs  are  less 
troubled  by  them  than  smaller  ones. 

Most  American  impounding  reservoirs  are  arranged  to 
have  water  drawn  from  their  surface-layers,  to  avoid  the 
odors  and  tastes  of  putrefaction  in  the  bottom  water;  but 
it  sometimes  happens  that  the  surface  water  is  even 
more  objectionable  than  the  bottom  water  because  of 
odors  and  tastes  of  living  and  dying  organisms. 


STRIPPING. 


21 


Stripping.  In  Massachusetts  more  attention  has  been 
given  to  protecting  the  quality  of  reservoir  waters  than 
elsewhere,  with  a  view  to  avoiding  objectionable  odors 
and  tastes. 

Shallow  flowage  has  been  cut  out  of  many  reservoirs, 
partly  by  diking  off  shallow  portions,  and  partly  by 
filling  them  with  material  excavated  from  other  shallow 
portions.  This  has  had  the  effect  of  reducing  the  area 
of  a  reservoir,  and  of  increasing  its  average  depth. 

But  by  far  the  most  extended  and  costly  work  has 
been  the  stripping.  By  stripping  is  meant  the  removal 
of  the  surface  soil  from  the  area  that  is  to  be  covered 
with  water.  At  least  eight  considerable  reservoirs,  in 
addition  to  many  smaller  ones,  have  been  stripped  in 
this  way,  namely: 


Reservoir. 

City  supplied. 

Area  in 
acres. 

Average 
depth 
in  feet. 

Capacity 
in  million 
gallons 

Wachusett  .    .    . 

Bostort  .    .    . 

4,200 

46 

63,100 

Sudbury      .    .    .    ,    ; 

Boston  .    .    . 

1,292 

18 

7,253 

Lower  Hobbs    . 

Cambridge    . 

467 

10 

I>450 

Framingham  No.  3  . 

Boston  .    .    . 

253 

15 

I,l83 

Hopkinton      .    . 

Boston  .    .    . 

185 

26 

1,521 

Upper  Holden  .    .    . 

Worcester  .    . 

I85 

17 

794 

Ashland      

Boston  .    .    . 

I67 

26 

1,464 

Lower  Holden 

Worcester  ,    . 

149 

15 

742 

The  object  of  stripping  has  been  to  remove  the  organic 
matter  of  the  surface  soil.  Where  this  has  been  thor- 
oughly done,  it  has  tended  to  improve  the  conditions  of 
the  water  in  the  reservoir.  In  the  older  reservoirs  pre- 
pared in  this  way  putrefaction  in  the  bottom  water  has 
not  taken  place  for  some  years  after  the  reservoirs  were 
built,  although  in  other  cases  putrefaction  seems  not  to 
have  been  entirely  prevented,  even  at  the  outsetc 


22  IMPOUNDING  RESERVOIR  SUPPLIES. 

The  removal  of  the  soil  also  seems  to  cut  off  a  part  of 
the  food  supply  for  objectionable  organisms,  and  the 
stripped  reservoirs  have  suffered  less  from  these  growths 
than  other  reservoirs  similarly  situated  but  not  stripped. 

But  stripping  does  not  prevent  objectionable  growths; 
it  only  reduces  them  somewhat,  and  it  does  not  always 
permanently  prevent  putrefaction  in  the  bottom  water. 

It  does  not  prevent  the  growths,  because  some  of  the 
worst  of  the  organisms  do  not  need  or  make  use  of 
the  organic  matter  of  the  soil  as  a  food  supply*  Instead, 
they  live  on  the  mineral  matters  of  the  water  and  the  air, 
and  with  the  aid  of  the  sunshine  they  build  up  their  own 
organic  matter  precisely  as  the  higher  plants  do  in  grow- 
ing in  soil.  Removing  the  soil  from  a  reservoir  site 
does  not  seriously  or  permanently  interfere  with  the 
growth  of  these  organisms.  Further,  it  cannot  be  de- 
pended upon  to  permanently  prevent  putrefaction,  be- 
cause in  our  climate  there  seems  to  be  an  inevitable 
accumulation  of  organic  matter  on  the  bottom  of  all 
ponds,  except  those  which  are  so  large  that  the  wind 
action  is  able  to  hold  the  growths  of  organisms  down, 
and  the  accumulation  of  the  bodies  of  dead  organism 
on  the  bottom  soon  furnishes  the  materials  for  putre- 
faction even  though  all  soil  with  its  organic  matter  was 
removed  at  the  start. 

This  accumulation  comes  from  the  bodies  of  organ- 
isms which  grow  in  the  sunshine  in  the  top  water  and 
then  settle  through  the  stagnant  bottom  water  to  the 
bottom.  It  is  inevitable  and  cannot  be  prevented.  It 
is  an  accumulation  of  this  general  character  which  has 
filled  with  peat  most  of  the  lakes  that  were  left  by  the 


THE  USE  OF  COPPER  SULPHATE.      23 

glacial  epoch,  and  has  changed  them  into  the  peat 
swamps  so  common  in  all  our  Northern  states. 

Stripping  is  an  expensive  process,  but  the  quality  of  a 
public  water  supply  is  an  important  matter,  and  in  some 
cases  the  cost  has  been  justified  by  the  improved  quality 
of  the  water. 

In  other  cases  there  seems  to  be  no  reason  to  doubt  that 
more  improvement  could  be  effected  in  other  ways,  at  less 
cost  as,  for  instance,  by  aeration  and  filtration  of  the  water , 

On  the  Use  of  Copper  Sulphate.  In  1904  Dr.  George  T. 
Moore,  of  the  United  States  Department  of  Agriculture, 
proposed  the  use  of  sulphate  of  copper  in  impounding 
reservoirs,  to  poison  the  organisms  which  produce  objec- 
tionable odors  and  tastes.  This  substance  is  extremely 
poisonous  to  some  of  the  organisms  and  only  moderately 
poisonous  to  man.  It  is  therefore  possible,  with  due 
care,  to  kill  the  algae  without  endangering  the  health  of 
the  people  who  use  the  water. 

The  method  of  treatment  proposed  and  generally  used 
is  to  put  weighed  quantities  of  the  copper  sulphate  in 
loose  cloth  bags  and  tow  them  back  and  forth  with  row- 
boats  through  the  water  of  the  reservoir  until  the  material 
is  dissolved.  One  part  of  copper  sulphate  in  from  four 
to  ten  million  parts  of  water  suffices  to  destroy  growths 
of  some  objectionable  organisms.  Others  require  larger 
doses.  Some  of  the  copper  combines  with  the  bodies 
of  the  organisms  and  settles  with  them  to  the  bottom,  and 
in  this  way  is  removed  from  the  water.  If  the  water  is 
hard,  more  copper  is  removed  in  this  way,  and  it  goes  out 
quicker.  If  the  water  is  afterwards  filtered  most  of  the 
remaining  copper  is  removed. 


24  IMPOUNDING  RESERVOIR  SUPPLIES. 

As  copper  is  but  slightly  poisonous  to  man,  there  does 
not  seem  to  be  any  real  danger  in  the  use  of  copper  in  this 
way,  or  even  in  the  use  of  the  somewhat  larger  doses 
which  have  occasionally  been  used  where  the  water  was 
very  bad. 

The  copper  kills  some  kinds  of  organisms,  but  not  all 
kinds,  and  to  some  extent  its  use  clears  the  way  for 
stronger  growths  of  the  forms  that  are  not  killed.  It 
therefore  changes  the  kind  of  growth  in  a  reservoir  to 
some  extent,  and  this  change  is  frequently  accompanied 
by  a  great  improvement  in  odors  and  tastes. 

The  use  of  copper  sulphate  does  not  prevent,  or  even 
materially  reduce,  putrefaction,  and  the  tastes  and  odors 
resulting  from  it. 

This  method  of  treating  water  is  cheap,  easily  and 
quickly  applied,  and  considerable  good  has  come  from  it. 
The  correction  is  only  partial,  however,  and  not  always 
permanent.  It  is  not  therefore  to  be  relied  upon  in  all 
cases. 

Color  in  Reservoir  Waters.  Most  reservoir  waters 
are  colored  yellow  to  a  greater  or  less  extent  by  peaty 
matter.  This  coloring  matter  is  extracted  from  dead 
leaves,  from  soil,  from  peat,  etc.  It  seems  to  be  the 
same  material  as  the  coloring  matter  of  tea,  and  it  is 
certainly  harmless.  But  it  makes  a  water  less  pleasing 
in  appearance,  and  great  efforts  have  been  rightly  made 
to  prevent  it  and  to  remove  it. 

When  a  colored  water  is  exposed  to  sunlight  it  is  grad- 
ually bleached.  A  long  period  of  exposure  is  required 
for  completing  bleaching,  but  a  notable  reduction  in 
color  due  to  this  cause  is  usually  found  in  all  considerable 


COLOR  IN  RESERVOIR  WATERS.  25 

impounding  reservoirs.  Some  of  the  Boston  reservoirs 
have  been  made  larger  than  would  otherwise  have  been 
necessary  and  desirable  for  the  sake  of  allowing  more 
bleaching  to  take  place  in  them. 

A  large  part  of  the  color  comes  from  swamps  upon 
the  catchment  areas.  When  swamps  are  drained,  the 
color  of  the  water  issuing  from  them  is  reduced. 

The  upper  Mississippi  is  a  highly  colored  stream. 
There  are  thousands  of  square  miles  of  swampy  land 
upon  its  catchment  area.  In  the  last  decade  much  of 
this  land  has  been  drained  to  allow  its  use  for  agricul- 
tural purposes.  Only  a  fraction  of  the  whole  amount 
of  swamp  area  has  been  drained,  but  the  change  thus 
far  made  has  reduced  to  a  noticeable  extent  the  color  of 
the  water  of  the  river  at  Minneapolis. 

In  the  Boston  water  works  thousands  of  acres  of 
swamp  upon  the  catchment  areas  of  the  various  reser- 
voirs have  been  drained  by  the  city,  with  the  consent  of 
the  owners  of  the  land,  for  the  purpose  of  reducing  the 
color  of  the  supply.  A  considerable  reduction  in  color 
has  been  so  made. 

If  there  were  no  other  ways  of  reducing  color,  bleach- 
ing in  reservoirs  and  drainage  of  swamps  would  be 
worthy  of  most  careful  attention  and  frequent  use.  But 
at  the  present  time  other  means  of  removing  color  are 
known  which  usually  accomplish  more  for  a  given  ex- 
penditure than  can  be  reached  in  these  ways.  These 
will  be  described  in  connection  with  methods  of  water 
purification. 


CHAPTER  II. 
WATER    SUPPLIES    FROM    SMALL    LAKES. 

THE  city  of  Rochester  takes  its  supply  from  Hemlock 
Lake,  thirty  miles  from  the  city  and  elevated  above  it  so 
that  water  flows  by  gravity  under  sufficient  pressure.  In 
the  same  way  the  city  of  Syracuse  uses  the  water  of 
Skaneateles  Lake. 

These  cities  were  fortunate  in  finding  these  lakes, 
which  are  really  impounding  reservoirs  ready-made  and 
suitable  for  their  needs.  Some  expenditures  were  nec- 
essary to  acquire  the  water  rights,  and  to  buy  some  of 
the  shores,  and  to  secure  sanitary  protection  of  the  qual- 
ity of  the  water;  but  broadly  speaking,  these  reservoirs 
were  gifts  of  nature  to  these  cities,  and  if  they  had  not 
been  there,  the  cities  might,  and  probably  would,  have 
spent  hundreds  of  thousands,  or  millions,  of  dollars  in 
building  reservoirs  less  suitable  for  their  purposes  than 
those  freely  provided  by  nature. 

In  taking  such  a  lake  with  a  limited  catchment  area, 
provision  must  be  made  for  raising  and  lowering  the 
water  surface  within  certain  limits.  This  is  done  by 
building  a  dam  at  the  outlet,  or  by  putting  in  an  outlet 
pipe  at  a  lower  level  than  the  natural  outlet,  or  by  doing 
both  at  once.  This  provides  the  necessary  storage 
capacity  to  hold  the  winter  and  spring  flood-flows,  and 

26 


NATURAL   RESERVOIRS.  27 

to  allow  them  to  be  drawn  and  used  when  needed  in  the 
dry  summer  months. 

And  when  this  is  done  the  natural  lake  serves  pre- 
cisely the  same  purpose  as  an  artificial  reservoir,  and 
the  water  is  subject  to  the  same  troubles.  The  sanitary 
protection  of  the  catchment  area,  the  stagnation  and 
putrefaction  of  the  bottom  water,  and  the  growth  of  or- 
ganisms in  the  top  water,  are  all  pretty  much  the  same 
as  in  artificial  reservoirs. 

On  the  whole,  the  waters  of  natural  lakes  and  ponds 
are  less  subject  to  objectionable  odors  and  tastes  than 
are  the  waters  of  artificial  reservoirs,  and  putrefaction  is 
less  troublesome,  but  the  difference  is  one  of  degree,  not 
of  kind. 

Growths  of  organisms  are  less  frequent  and  strong, 
probably  because  the  lakes  are  larger  and  deeper  and 
more  completely  subject  to,  and  controlled  by,  wind 
action,  and  putrefaction  is  less  prevalent  because  there 
are  fewer  organisms  growing  in  the  top  water  and 
settling  down  into  the  bottom  water  to  cause  it. 

The  advantages  of  taking  a  natural  lake  for  a 
reservoir  are  so  great  and  obvious  that  it  has  nearly 
always  been  done  where  circumstances  have  per- 
mitted. Both  New  York  and  Boston  have  utilized  a 
number  of  lakes  upon  their  catchment  areas  in 
this  way,  though  the  reservoirs  mainly  depended 
upon  have  been  artificial.  Portland,  Maine,  is  sup- 
plied from  Sebago  Lake.  St.  Paul  is  supplied  from 
a  number  of  small  lakes.  In  this  case  the  lakes  are 
not  high  enough  for  a  gravity  supply,  and  the  water 
is  pumped. 


28         WATER  SUPPLIES  FROM  SMALL  LAKES. 

Throughout  the  northern  part  of  the  United  States, 
where  the  country  has  been  glaciated,  and  small  lakes 
abound,  innumerable  smaller  cities  and  villages  are  sup- 
plied from  them,  sometimes  by  gravity  and  sometimes 
by  pumping. 


CHAPTER  III. 
SUPPLIES  FROM  THE  GREAT  LAKES. 

MOST  of  the  cities  on  the  shores  of  the  Great  Lakes 
use  water  taken  from  them  by  pumping.  The  largest  of 
these  cities  in  the  United  States  are  Chicago,  Cleveland, 
Buffalo,  Detroit,  Milwaukee,  and  Duluth.  They  also  in 
general  put  their  sewage  into  the  same  water  from  which 
their  supplies  are  taken.  And  the  relations  between  the 
water  supply  and  the  sewage  are  most  interesting  and 
important. 

In  one  respect  two  of  the  cities  are  more  favorably 
situated  than  the  others.  Buffalo  and  Detroit  are  upon 
strong  running  streams  at  the  outlets  of  the  lakes,  where 
it  is  possible  to  take  the  water  supplies  from  points 
above  the  cities,  and  to  discharge  the  sewage  at  points 
below,  with  little  likelihood  of  subsequent  mixing.  And 
in  this  respect  the  water  problems  of  these  cities  are 
much  simpler  than  those  of  the  others. 

Buffalo  has  the  advantage  over  Detroit  that  the  water 
comes  to  it  more  directly  from  the  lake  and  with  less 
chance  of  pollution.  Detroit  is  sixty  miles  below  the  out- 
let of  Lake  Huron,  and  in  that  distance  there  is  oppor- 
tunity for  much  pollution.  This  pollution  comes  both 
from  the  drainage  of  the  considerable  area  reaching  the 
river  in  this  distance  and  from  the  discharge  of  sewage 
from  the  cities  directly  upon  its  banks.  And  this  pollu- 

29 


30  SUPPLIES  FROM  THE  GREAT  LAKES. 

tion  by  sewage  is  an  important  matter  even  with  a  dilu- 
tion as  great  as  that  in  the  Detroit  River,, 

Milwaukee  and  Duluth  are  fortunate  in  that  they  are 
able  to  reach  the  lakes  with  intakes  in  deep  water  at 
points  where  there  seem  to  be  fairly  definite  currents 
bringing  fresh,  clean  water  from  the  body  of  the  lake  to 
the  intakes,  and  excluding  the  city  sewage.  These  cur- 
rents seem  to  be  dependable,  although  it  may  be  that 
they  are  sometimes  reversed  temporarily  by  strong  winds. 
Certainly  the  present  indications  are  that  the  water 
obtained  from  them  is  at  least  comparatively  free  from 
sewage. 

Chicago  and  Cleveland  have  suffered  most  from  the 
mingling  of  their  own  sewage  with  their  water  supplies, 
and  their  troubles  in  this  respect  are  not  over.  Chicago, 
it  is  true,  has  cut  a  drainage  canal  to  keep  her  sewage 
from  entering  the  lake,  and  to  take  it  instead  through 
tributaries  to  the  Mississippi  River,  at  a  cost  of  over 
forty  million  dollars.  But  even  now  that  the  canal  is  in 
operation,  so  much  polluting  material  finds  its  way  to  the 
lake  that  the  water  is  polluted  at  times  for  a  long  distance 
out.  Cleveland  has  no  drainage  canal,  but  she  is  smaller 
than  Chicago,  and  the  conditions  of  the  water  in  the 
lakes  near  the  two  cities  probably  are  not  greatly  different. 

Both  lakes  are  comparatively  shallow  and  are  stirred 
to  the  bottom  by  heavy  winds,  at  least  as  far  out  as  the 
water  works  intakes  have  yet  been  built.  Both  cities 
have  spent  millions  driving  tunnels  out  under  the  bot- 
toms of  the  lakes  for  the  purpose  of  securing  water  free 
from  contamination.  Both  have  succeeded  in  getting 
better  water  in  this  way,  and  both  have  failed  to  get 


PROBLEM  OF  CONTAMINATION.  31 

thoroughly  good  water,  even  with  intakes  located  four 
or  five  miles  from  shore;  and  both  cities  have  suffered 
severely  at  times,  and  perhaps  a  little  all  the  time,  from 
sickness  and  death  caused  by  the  pollution  of  the  lake 
waters  by  their  own  sewage. 

The  Great  Lakes  are  so  large,  and  the  dilution  and 
time  intervals  and  exposure  to  sun  and  air  are  so  great 
that  there  is  no  chance  of  infection  being  carried  from 
one  of  the  great  cities  to  another.  Chicago's  sewage 
would  not  endanger  the  purity  of  Detroit's  water  supply, 
even  with  no  drainage  canal.  The  little  city  of  St.  Clair, 
with  2543  inhabitants,  only  45  miles  away,  is  far  more 
dangerous  to  Detroit.  In  the  same  way  Detroit's  sewage 
is  harmless  at  Cleveland,  and  Cleveland's  sewage  is 
harmless  at  Buffalo. 

Besides  the  large  cities  mentioned  there  are  a  hundred 
smaller  places  upon  the  shores  of  the  lakes  which  take 
their  water  from  them,  and  there  are  some  other  cities 
which  do  not  use  lake  water.  Toledo,  Ohio,  finds  it 
cheaper  and  better  to  use  Maumee  River  water  than  to 
put  in  the  expensive  intake  and  appurtenances  which 
would  be  necessary  to  secure  lake  water  beyond  the 
influence  of  local  pollution. 

In  the  smaller  cities  upon  the  lakes  the  mingling  of  the 
sewage  and  water  may  be  relatively  just  as  important  as 
in  the  larger  ones.  They  have  less  money  to  spend; 
their  intakes  do  not  go  out  so  far;  their  sewers  are  apt  to 
discharge  at  the  nearest  point,  sometimes  directly  in  front 
of  the  water  works  intake;  the  water  may  be  shallow, 
and  stirred  by  the  wind  to  the  bottom;  and  in  short, 
Menominee's  sewage  in  Menominee's  water  may  be 
just  as  bad  as  Chicago's  sewage  in  Chicago's  water. 


CHAPTER  IV. 


WATER   SUPPLIES   FROM   RIVERS. 

THE  following  large  cities  in  the  United  States  take 
their  water  supplies  from  large  rivers: 


Place. 

Population. 
1910. 

Water 
from  what 
river. 

Drainage 
area 
above 
intake 
sq.  miles. 

Urban 
population 
above 
intake 
1910. 

!N 
Urban, 

lation 
Per 
sq.mile. 

Philadelphia  

1,549,008 

f  Delaware 
\  Schuylkill 

8,186 
1,915 

360,994 
257,415 

44 
134 

St  Louis  

687,029 

Mississippi 

700.663 

5,750,931 

g 

Pittsburgh. 

533  905 

Allegheny 

ii  400 

306  117 

Cincinnati. 

363  591 

Ohio 

72  400 

2  342  IO3 

02 

New  Orleans  

339,075 

Mississippi 

1,261,084 

12,565,811 

10 

Washington  

331,069 

Potomac 

11,476 

104,980 

9 

Minneapolis  

301,408 

Mississippi 

19,585 

34,438 

2 

Kansas  City,  Mo  . 

248,381 

Missouri 

163,752 

987,624 

6 

Indianapolis  

233,650 

White 

1,820 

76,019 

42 

Providence  

224,326 

Pawtuxet 

o 

o 

Louisville  

223,928 

Ohio 

91,000 

3,247,l62 

36 

Toledo  

168,497 

Maumee 

6,723 

I57,5IO 

23 

Richmond  

127,628 

James 

6,800 

29,494 

4 

Paterson  

125,600 

Passaic 

773 

24,9O5 

32 

Omaha 

124  096 

Missouri 

322  500 

160  684 

O  5 

Nashville 

no  364 

Cumberland 

12  8OO 

25  894 

2 

Albany  

100,253 

Hudson 

8,240 

472,255 

57 

In  addition  to  these  a  very  large  number  of  smaller  cities 

and  towns  take  their  water  from  the  rivers  of  the  country. 

In  large  parts  of  the  country  the  rivers  are  the  only 

32 


SANITARY  ASPECTS.  33 

adequate  available  sources  of  supply,  and  they  will  always 
so  remain. 

Sanitary  Aspects  of  River  Water  Supplies.  From  an 
hygienic  standpoint  the  succession  of  cities  and  manufac- 
turing establishments  on  the  same  river,  and  the  combined 
use  of  the  river  as  a  sewer  and  source  of  water  supply  is 
most  significant. 

On  some  rivers,  like  the  Merrimack,  Hudson,  Dela- 
ware, Ohio,  Missouri,  and  Mississippi,  this  succession  is 
particularly  impressive,  and,  when  the  water  has  been 
used  in  its  raw  or  unpurified  state,  sickness  and  death 
have  resulted,  and  thousands  of  lives  have  been  lost  in 
this  way. 

The  relation  of  water  supply  to  sickness  and  death  has 
been  shown  with  force  in  many  cities,  notably  at  Lowell 
and  Lawrence,  Massachusetts,  at  Albany,  New  York,  at 
Jersey  City  and  Newark,  New  Jersey,  and  abroad  at 
London,  Paris,  Hamburg,  Altona,  Berlin,  etc.  Some  of 
these  cities  have  since  abandoned  the  objectionable  sup- 
plies. Others  have  installed  purification  works  which 
have  removed  the  poisonous  qualities  of  the  river  waters. 

At  Lowell  a  ground  water  supply  was  secured  to  take 
the  place  of  the  polluted  river  water;  at  Jersey  City  and 
Newark  new  supplies  from  impounding  reservoirs  were 
substituted;  while  Lawrence  and  Albany  constructed 
purification  works. 

Substitute  supplies  have  also  been  proposed  in  a  num- 
ber of  other  large  cities.  In  some  cases  such  supplies 
could  be  obtained,  though  often  at  greater  expense  than 
can  now  be  afforded;  but  in  many  or  most  cases  the  river 
water  is  the  only  water  that  can  be  obtained  in  sufficient 


34  WATER  SUPPLIES  FROM  RIVERS. 

amount.  Where  this  is  the  case  there  is  no  alternative. 
The  river  water  must  continue  to  be  the  source  of 
supply. 

It  is  possible  to  purify  sewage  before  discharging  it 
into  .rivers.  If  all  the  cities  and  towns  purified  their 
sewage,  and  if  all  manufacturing  establishments  (which 
sometimes  contribute  as  much  as  the  cities  to  the  pollu- 
tion of  the  streams)  did  the  same,  then  the  river  waters 
of  the  country  would  be  less  polluted,  and  would  be 
more  desirable  as  sources  of  public  water  supply. 

Some  people  believe  that  all  sewage  and  wastes  should 
be  so  purified  before  being  discharged,  and  that  the  rivers 
should  be  so  protected  from  pollution. 

A  few  large  cities,  notably  Worcester  and  Providence, 
do  partially  purify  their  sewage,  and  many  smaller  ones 
do  so.  But  in  very  few  cases  has  this  been  done  to  pre- 
vent the  pollution  of  a  public  water  supply  taken  from 
the  stream  below  the  sewer  outlet.  Sewage  has  usually 
been  purified  only  in  those  cases  where  a  local  nuisance 
was  created  in  the  stream  below  the  outfall,  or  at  least 
where  such  a  nuisance  was  anticipated,  rightly  or  wrongly, 
in  case  crude  discharge  was  permitted. 

By  local  nuisance  is  meant  the  discoloration  of  the 
water,  the  presence  of  floating  substances  objectionable 
in  appearance,  the  deposition  of  sewage  mud  on  the  bed 
of  the  stream,  and  the  production  of  offensive  odors. 
All  of  which  make,  or  tend  to  make,  the  stream  and 
its  banks  and  neighborhood  less  desirable  for  bathing, 
boating,  navigation,  business,  residence,  and,  in  short, 
less  useful  to  the  public,  and  especially  to  those  living  in 
or  often  passing  the  locality. 


SANITARY  ASPECTS.  35 

Now,  whether  or  not  a  local  nuisance  is  caused  by  the 
discharge  of  sewage  depends  upon  the  relative  amounts 
of  sewage  and  flowing  water,  and  upon  the  rapidity  of 
current  and  the  temperature,  etc.  These  matters  need 
not  be  here  discussed.  It  will  suffice  to  state  that  there 
are  numerous  cases  where  local  nuisances  are  produced 
which  would  amply  justify  the  purification  of  the  sewage 
to  prevent  them,  but  that  in  other  cases,  and,  in  fact,  in 
a  great  majority  of  cases  where  sewage  is  discharged 
into  rivers,  there  does  not  result  any  local  nuisance  which 
would  justify,  to  prevent  it,  the  expenditure  of  the  money 
necessary  to  purify  the  sewage,  or,  even  if  the  work  could 
be  done  for  it,  of  one-tenth  of  the  required  sum. 

Where  sewage  is  purified  to  prevent  a  local  nuisance 
in  a  stream  from  which  a  public  water  supply  is  taken 
below,  then  certainly  the  purification  is  advantageous  to 
the  quality  of  that  supply;  but  this  is  the  exceptional 
case  and  not  the  common  one.  To  set  about  cleaning 
up  the  rivers  of  the  country  for  the  purpose  of  improving 
the  quality  of  the  public  water  supplies  would  involve 
the  purification  of  sewage  from  thousands  of  cities  and 
towns  where  that  was  the  only  reason  for  the  purifica- 
tion, or,  in  other  words,  where  there  was  no  local  nui- 
sance produced  by  the  discharge  of  crude  sewage. 

To  protect  the  water  supply  of  Louisville,  it  would  be 
necessary  to  purify  the  sewage  of  Cincinnati,  Pittsburgh, 
and  hundreds  of  smaller  cities  upon  the  Ohio  River  and 
its  tributaries.  From  the  standpoint  of  local  nuisance, 
the  purification  of  the  sewage  from  a  few  of  these  cities 
is  already  necessary,  and,  as  time  goes  on  and  population 
increases,  it  will  be  necessary  to  treat  the  sewage  from 


36  WATER  SUPPLIES  FROM  RIVERS. 

an  ever  increasing  number  of  cities  in  this  way;  but  the 
fact  must  be  fully  recognized  that  the  discharge  of  crude 
sewage  from  the  great  majority  of  cities  is  not  locally 
objectionable  in  any  way  to  justify  the  cost  of  sewage 
purification. 

Looking  at  the  whole  matter  as  one  great  engineering 
problem,  it  is  clearly  and  unmistakably  better  to  purify 
the  water  supplies  taken  from  the  rivers  than  to  purify  the 
sewage  before  it  is  discharged  into  them. 

It  is  very  much  cheaper  to  do  it  in  this  way.  The 
volume  to  be  handled  is  less,  and  per  million  gallons  the 
cost  of  purifying  water  is  much  less  than  the  cost  of 
purifying  sewage. 

It  is  also  very  much  more  effective  to  treat  the  water, 
because  the  methods  of  water  purification  are  more 
efficient  in  stopping  germs  of  disease  than  are  the 
methods  of  sewage  purification. 

It  is  also  more  effective,  because  all  the  water  used 
can  be  with  certainty  treated,  while  it  is  well  known  that 
very  few  sewage  purification  works  treat  all  the  sewage 
from  the  districts  which  they  serve.  There  are  storm 
overflows;  there  is  the  street  wash  that  may  not  pass 
through  the  sewers;  there  are  the  thousand  minor  pollu- 
tions that  practically  cannot  be  stopped,  even  though 
the  sewage  is  treated  and  all  reasonable  precaution  taken 
in  connection  with  it. 

It  is,  therefore,  both  cheaper  and  more  effective  to 
purify  the  water,  and  to  allow  the  sewage  to  be  dis- 
charged, without  treatment,  so  far  as  there  are  not  other 
reasons  for  keeping  it  out  of  the  rivers.  It  seems 
unlikely  that  a  single  case  could  be  found  where  a  given 


TURBIDITY.  37 

and  reasonably  sufficient  expenditure  of  money  wisely 
made  could  do  as  much  to  improve  the  quality  of  a  given 
water  supply  when  expended  in  purifying  sewage  above, 
as  could  be  secured  from  the  same  amount  of  money  in 
treating  the  water.  Usually  I  believe  that  there  would 
be  a  wide  ratio:  that  one  dollar  spent  in  purifying  the 
water  would  do  as  much  as  ten  dollars  spent  in  sewage 
purification. 

The  water  works  man  therefore  must,  and  rightly 
should,  accept  a  certain  amount  of  sewage  pollution  in 
river  water,  and  make  the  best  of  it.  Taking  it  up  in 
this  way  he  will  master  the  situation  by  purifying  the 
water.  Success  in  supplying  good  water  cannot  be 
otherwise  reached. 

The  general  project  of  keeping  all  sewage  out  of  rivers 
is  attractive,  and  it  will  always  have  its  earnest  advocates ; 
but  it  is  not  a  practical  proposition  and  it  is  not  necessary. 
It  is  not  even  desirable,  when  the  greater  good  to  be 
secured  by  a  given  expenditure  in  other  directions  is  taken 
into  account.  Although  the  public  is  ignorant  of  such 
matters,  still,  in  a  general,  indefinite  sort  of  a  way  it  does 
even  now  understand  some  of  the  elements  of  the  situa- 
tion, and  as  time  goes  on  it  is  bound  to  understand  them 
better. 

Turbidity.  After  sanitary  qualities  there  is  no  feature 
of  river  water  supplies  of  more  general  interest  and 
importance  than  the  turbidity,  or  muddiness  of  the 
water.  All  river  waters  are  more  or  less  turbid,  but  the 
differences  are  very  great  indeed.  They  come  principally 
from  differences  in  character  of  the  catchment  areas. 

The  Merrimack  and  Connecticut  Rivers  in  New  Eng- 


38  WATER  SUPPLIES  FROM  RIVERS. 

land,  draining  areas  largely  covered  with  glacial  drift  of 
a  sandy  character,  are  but  little  subject  to  turbidity.  As 
an  annual  average  they  do  not  carry  more  than  ten  parts 
per  million  of  suspended  matter.  Usually  they  carry  much 
less  than  even  this  small  amount;  but  once  or  twice  in  a 
year  there  is  a  flood  which  washes  away  some  of  the 
banks  and  carries  along  a  considerable  amount  of  silt,  but 
even  this  rapidly  settles  out  when  opportunity  presents. 

Of  the  same  general  character  in  this  respect  are  the 
waters  of  the  Upper  Hudson  and  of  the  rivers  of  Northern 
New  York,  Michigan,  Wisconsin,  and  Minnesota,  in- 
cluding the  upper  Mississippi,  and  also  most  of  those  of 
northern  New  Jersey.  Small  streams  rising  near  the 
coast  and  in  the  sand  hills  back  of  it  are  also  found  here 
and  there  all  down  the  Atlantic  coast  which  are  not 
greatly  subject  to  turbidity.  Some  waters  from  moun- 
tainous regions  where  the  rocks  are  hard  are  also  nearly 
free  from  turbidity.  Such  streams  are  found  near  the 
Pacific  coast  in  the  Sierra  and  coast  ranges. 

Speaking  generally,  the  rest  of  the  river  waters  of  the 
country  are  more  turbid.  Some  of  them,  it  is  true,  are 
usually  fairly  clear,  and  are  only  subject  to  excessive  tur- 
bidity for  short  intervals  in  infrequent  floods.  Such  are 
the  Delaware,  the  Allegheny,  and  some  of  the  streams  in 
northern  Ohio,  Indiana,  and  Illinois. 

Farther  south  the  turbidities  run  higher  and  also  last 
longer.  The  larger  streams  flowing  to  the  Atlantic  coast 
south  of  the  Delaware  have  very  turbid  periods  and  are 
usually  subject  to  very  rapid  fluctuation  in  turbidity.  A 
sudden  storm  may  increase  it  a  hundredfold  in  a  few 
hours.  The  Ohio  River  and  its  southern  tributaries  are 


COLOR  IN  RIVER  WATERS.  3£ 

subject  to  large  amounts  of  turbidity,  and  muddy  water 
sometimes  flows  in  them  continuously  for  much  longer 
periods  than  in  the  Atlantic  coast  streams. 

The  Missouri  River  carries  the  largest  amount  of  sedi- 
ment of  any  of  the  rivers  largely  used  for  water  supply, 
and  as  an  annual  average  the  amount  runs  as  high  as 
1 200  or  1500  parts  per  million.  In  winter  it  falls  to  200 
parts  or  less,  while  in  midsummer  it  rises  for  weeks,  and 
even  months,  to  5000  parts  or  more. 

The  Mississippi  at  Minneapolis  is  not  much  subject 
to  turbidity.  As  it  flows  south  it  becomes  more  turbid, 
but  even  as  far  down  as  where  the  Missouri  joins  it,  it  is 
comparatively  a  clear  water  stream.  Below,  it  takes 
more  largely  of  the  character  of  the  Missouri.  The 
amount  of  sediment  is  less  than  in  the  Missouri,  but  the 
Ohio  and  other  tributaries  bring  to  it  a  sediment  that  is 
more  finely  divided  and  more  difficult  of  removal,  so 
that  for  practical  purposes  the  river  at  New  Orleans  is 
as  turbid  as  it  is  at  St.  Louis,  even  though  the  analytical 
results  show  less  suspended  matter. 

Color  in  River  Waters.  The  color  of  water  has  already 
been  mentioned  in  connection  with  impounding  reser- 
voirs. The  color  referred  to  is  the  yellow  color  extracted 
from  dead  leaves,  from  swamps,  etc.  This  color  is  in 
solution,  and  it  is  to  be  sharply  distinguished  from  the 
turbidity  which  results  from  clay  and  other  suspended 
matter  in  the  water.  Turbidity  is  frequently  spoken  of 
as  color;  and  when  the  material  composing  it  is  colored, 
as  for  instance,  red  clay,  it  is  certainly  correct  to  speak 
of  it  in  this  way.  But  for  the  purpose  of  this  discussion 
color  means  only  the  yellow  coloring  matter  that  is  in 


40  WATER  SUPPLIES  FROM  RIVERS. 

solution.  This  is  the  meaning  that  is  commonly  adopted 
by  water  analysts,  and  the  distinction  is  necessary. 

In  a  general  way,  colored  waters  are  found  in  those 
regions  where  turbidity  is  not  found.  But  there  are  some 
exceptions  to  this  rule.  The  upper  Delaware,  among  the 
larger  rivers,  is  comparatively  free  from  color,  and  also 
is  usually  free  from  turbidity.  There  are  many  smaller 
streams  of  which  this  is  also  true.  Spring  water  streams, 
in  sand  hill  districts,  and  mountain  streams  frequently 
have  these  qualities.  On  the  other  hand,  the  upper 
Mississippi  is  a  highly  colored  stream,  and  it  is  also 
occasionally  moderately  turbid. 

In  general,  water  flowing  from  swamps  is  colored,  and 
in  a  rough  way  the  color  of  a  river  water  is  a  measure  of 
the  amount  and  character  of  the  swampy  area  upon  its 
catchment  area. 

Many  of  the  smaller  streams  of  the  north,  from  Maine 
to  Minnesota,  are  highly  colored.  So  also  are  the  smaller 
streams  from  the  swamps  near  the  coast  flowing  to  the 
Atlantic  all  the  way  down  the  coast  to  Florida.  Some 
large  rivers  are  colored  to  an  extent  which  affects  materi- 
ally their  value  for  water  supply  purposes,  although  they 
are  never  as  highly  colored  as  some  of  the  smaller  streams. 
Among  the  rivers  colored  so  as  to  affect  their  value,  and 
which  are  important  sources  of  public  water  supply,  may 
be  mentioned  the  Merrimack,  Hudson,  Black,  Passaic, 
Grand,  and  Mississippi  Rivers.  There  are  also  many 
others  supplying  smaller  cities. 

Turbidity  and  color  render  water  less  attractive,  less 
desirable,  and  less  valuable  for  public  supply.  They  can 
be  removed  by  purification  methods,  and  their  removal 


COLOR  IN  RIVER  WATERS.  41 

is  now  generally  demanded,  although  there  are  still  many 
cities  supplied  with  water  generally  regarded  as  good  but 
which  is  subject  to  them  in  considerable  amounts.  This 
is  especially  true  of  color. 

It  is  only  within  the  last  few  years  that  accurate 
records  of  turbidity  and  color  have  been  kept.  Even 
now  they  are  kept  by  only  a  part  of  the  water  works  that 
are  affected  by  them;  and  naturally  even  less  is  known 
about  the  turbidities  and  colors  of  the  waters  of  rivers 
that  are  not  used  for  water  supplies.  Our  knowledge  of 
the  general  distribution  and  range  of  turbidity  and  color 
is  far  short  of  what  could  be  desired.  It  is  being  added 
to  rapidly,  however. 


CHAPTER  V. 
GROUND    WATER    SUPPLIES. 

WATER  drawn  from  the  ground  by  wells  or  taken  from 
springs  is  called  ground  water,  and  this  source  of  supply 
is  a  most  important  one. 

It  is  easier  in  proportion  to  get  a  little  ground  water 
than  to  get  a  larger  amount,  and  for  this  reason  ground 
water  supplies  are  more  generally  available  for,  and  better 
adapted  to,  the  needs  of  small  places  than  of  large  cities. 

If  the  water  supplies  of  the  country  could  be  all  counted 
up,  each  plant  counting  for  one  regardless  of  its  size,  it 
would  be  found  that  the  ground  water  supplies  were 
more  numerous  than  those  of  any  other  kind,  probably 
in  fact  more  numerous  than  all  the  others  put  together. 
But  as  the  average  size  of  the  ground  water  supplies  is 
small,  the  total  amount  of  water  supplied  from  them 
would  be  much  smaller  than  that  supplied  from  impound- 
ing reservoirs,  or  from  rivers. 

In  Europe  ground  water  supplies  have  been  secured 
for  many  large  cities.  There  are  no  corresponding  de- 
velopments in  America.  The  reasons  for  the  greater 
use  of  this  method  of  supply  in  Europe  are: 

ist:  Smaller  quantity  of  water  required  per  capita. 

2d:  More  favorable  geological  conditions. 

3d:  More  study  given  to  the  subject,  and  greater 
efforts  made  to  secure  them,  especially  in  Germany. 

42 


FROM  SAND  AND  GRAVEL  DEPOSITS.          43 

Without  discussing  these  points  in  detail  it  may  be 
said  that  few  large  American  cities  are  situated  where 
there  are  sufficient  beds  of  sand  and  gravel,  or  other 
previous  formations  to  yield  water  for  their  supply,  such 
as  exist  over  a  considerable  part  of  central  and  northern 
Europe,  and  which  have  been  drawn  upon  most  success- 
fully by  even  the  largest  cities. 

Ground  Water  from  Sand  and  Gravel  Deposits.  Occa- 
sionally there  are  locations  where  such  supplies,  com- 
parable to  the  more  important  European  supplies  can  be 
secured  in  America.  Of  these  none  is  more  favorable 
than  that  of  the  Brooklyn  water  works  of  the  city  of  New 
York.  Of  the  total  supply  of  142,000,000  gallons  daily, 
96,000,000  gallons,  or  68  per  cent,  is  obtained  from  the 
ground,  mostly  from  tubular  wells  driven  in  the  coarse, 
open  sand  and  gravel.  These  wells  are  in  groups,  each 
group  being  pumped  by  a  pumping  station,  which 
throws  the  water  into  a  collecting  conduit,  which  takes 
it  to  other  pumps,  which  finally  raise  it  for  the  city  service. 
The  ground  water  is  not  kept  separate,  but  is  mixed  in 
the  conduit  with  the  pond  and  reservoir  waters,  which 
make  up  the  balance  of  the  supply. 

Separating  the  works  into  so  many  small  units,  each 
with  its  own  pumping  station,  adds  greatly  to  the  cost 
of  securing  the  water,  but  either  this  or  its  equivalent 
seems  to  be  necessary. 

Only  so  much  water  can  be  secured  from  a  square 
mile  of  ground.  The  amount  depends  upon  the  rain- 
fall, upon  the  evaporation  from  the  surface  of  the  ground 
and  from  the  vegetation,  and  upon  the  amount  of  storage 
in  the  pores  of  the  soil.  And  all  these  matters  may  be 


44  GROUND  WATER  SUPPLIES. 

computed  in  much  the  same  way  that  the  yield  of  an 
impounding  reservoir  can  be  calculated.  The  yield  is 
measured  by  the  rainfall,  in  a  dry  year,  less  the  evapo- 
ration; and  the  available  yield  is  either  this  amount,  or 
that  part  of  it  which  can  be  maintained  as  a  steady  flow 
throughout  the  year  by  the  storage  in  the  pores  of  the 
earth.  Most  of  the  available  yield  is  collected  during 
the  winter  when  evaporation  is  slight,  and  the  supply 
must  be  maintained  through  the  summer  by  the  reserve 
thus  accumulated. 

At  Brooklyn  the  conditions  for  storage  are  most  favor- 
able, and  it  is  estimated  that  750,000  gallons  per  day  can 
be  drawn  from  each  square  mile  of  catchment  area. 

Water  flows  through  sand  only  with  some  difficulty. 
From  a  given  pumping  station  it  is  only  possible  to  draw 
the  water  for  a  limited  distance.  This  distance  depends 
upon  the  depth  and  coarseness  of  the  sand.  The  area 
that  can  be  served  by  one  pumping  station  is  consider- 
ably extended  by  the  use  of  wells  at  some  distance  from 
each  other,  connected  by  pipe  lines  leading  to  the  pumps. 
But  practically  there  is  a  limit,  and  the  only  way  to 
secure  a  large  quantity  of  water  is  by  the  use  of  a  number 
of  comparatively  small  pumping  stations,  separated  so 
as  not  to  draw  from  the  same  territory.  In  Brooklyn, 
to  secure  96,000,000  gallons  of  ground  water  per  day, 
twenty-four  separate  pumping  stations  are  used.  From 
one  infiltration  gallery  15,000,000  gallons  per  day  are 
obtained.  Otherwise  the  greatest  average  quantity  of 
water  from  one  station  does  not  exceed  6,000,000  gallons 
daily.  And  the  average  quantity  from  one  station  is 
only  about  4,000,000  gallons  daily. 


FROM  SAND  AND  GRAVEL  DEPOSITS.  45 

The  favorable  conditions  at  Brooklyn  extend  over  a 
considerable  area  on  Long  Island,  and  also  in  southern 
New  Jersey.  In  this  area  there  are  many  smaller  ground 
water  supplies.  Of  these  the  one  at  Camden,  N.  J., 
deserves  special  mention.  The  water  is  lifted  by  com- 
pressed air,  from  wells  extending  over  a  considerable 
area  and  forwarded  to  one  central  pumping  station.  The 
air  is  compressed  at  this  station,  and  is  carried  to  the 
wells  in  wrought  iron  pipes.  By  this  means  an  unusually 
large  amount  of  water  is  handled  at  one  station.  There 
is  an  economy  in  labor,  but  the  use  of  coal  is  not  re- 
duced, as  the  compressed  air  is  not  an  efficient  means 
of  transmitting  power. 

The  compressed  air  method  of  pumping  is  extensively 
used  for  raising  ground  water  to  the  surface  of  the 
ground.  It  is  used  both  where  the  wells  are  far  removed 
from  the  pumping  station,  and  where  the  water  level  in 
the  wells  is  too  far  below  the  pumps  to  permit  of  its  being 
taken  directly  by  them. 

In  Camden  (pop.  94,538),  the  wells  are  close  to  the 
Delaware  River,  and  the  amount  of  water  obtainable  is 
increased  by  taking  river  water  over  the  surface  of  some 
of  the  ground  about  the  wells.  This  water  niters  through 
the  sand  slowly  and  is  well  purified.  This  method 
of  adding  to  the  yield  of  wells  is  used  at  some  places 
in  Germany  and  France. 

Memphis,  Tenn.  (pop.  131,105),  is  probably  the 
largest  city  in  the  United  States  supplied  entirely  with 
water  drawn  from  sand  and  gravel  deposits.  In  this  case 
the  water-bearing  area  is  several  hundred  feet  below  the 
surface  and  is  below  a  clay  layer. 


46  GROUND  WATER  SUPPLIES. 

Lowell,  Mass.  (pop.  106,294),  has  had  three  stations 
draining  different  areas  of  glacial  drift,  but  at  present 
the  whole  supply  is  maintained  from  two  of  them.  Of 
these  the  one  yielding  the  larger  quantity  of  water  is  on 
the  bank  of  the  Merrimack  River. 

Filter  galleries,  or  excavations  in  sandy  materials  near 
river  banks,  have  been  used  in  the  past.  At  present  tub- 
ular wells  are  usually  preferred.  It  makes  no  difference 
with  the  quality  of  the  water  which  is  used.  The  wells 
allow  the  water  to  be  drawn  at  a  lower  level,  and  this 
tends  to  the  drainage  of  a  greater  area,  thereby  securing 
a  larger  quantity  of  water  at  one  station. 

Formerly  many  towns  and  cities  were  supplied  with 
ground  water  from  gravel  deposits  which  are  now  sup- 
plied with  water  from  other  sources.  The  change  has 
usually  been  made  because  the  ground  water  works 
were  not  able  to  supply  the  increasing  quantities  of  water 
required  by  rapidly  growing  populations.  To  a  certain 
point,  limited  by  the  area  of  collecting  surface  and  storage 
capacity  in  the  sand,  the  quantity  of  water  obtained  can 
be  increased,  but  this  limit  is  reached  sooner  or  later. 

When  the  supply  is  derived  in  part  from  infiltration 
from  a  neighboring  river,  there  is  often  or  usually  a  grad- 
ual decrease  in  the  amount  of  water  available.  This  is 
because  the  pores  in  the  filtering  material  become  filled 
with  the  sediment  of  the  river  water  which  enters  them. 
In  some  torrential  streams  the  filtering  surface  is  renewed 
from  time  to  time,  but  usually  this  does  not  occur,  and 
there  is  no  way  of  renewing  the  source  when  its  capacity 
is  reduced  in  this  way. 

Wells  in  Sandstone  Rock.  Wells  in  porous  sandstone 


WELLS  IN  SANDSTONE  ROCK.  47 

rock  are  often  used  where  such  rock  exists.  The 
Marshall  and  Potsdam  sandstones  underlying  parts 
of  Michigan,  Illinois,  Wisconsin,  and  Minnesota,  are 
used  extensively  for  supplying  towns  and  small  cities. 
Jackson,  Mich.  (pop.  31,433),  is  one  of  the  largest  cities 
so  supplied. 

The  method  of  driving  the  wells  differs  from  that  of 
driving  wells  in  sand,  but  the  collection,  storage,  and  flow 
of  water  are  precisely  the  same.  The  cementing  ma- 
terial which  binds  what  would  otherwise  be  loose  sand 
into  a  solid  rock  often  seems  to  offer  but  little  resistance 
to  the  flow  of  water,  and  the  sandstone,  for  water  supply 
purposes,  acts  as  so  much  sand  would  do. 

Most  of  the  sand  deposits  of  the  country  are  not  prac- 
tically available  for  water  supply  purposes  because  the 
grains  of  sand  are  too  small,  and  the  flow  of  water  through 
them  is  too  slow.  It  is  only  the  coarse-grain  sands  that 
are  practically  available.  In  the  same  way  there  is  a 
great  difference  in  sandstones.  Only  the  coarse-grained 
ones  yield  water  freely,  and  some  of  the  most  extensive 
formations  are  not  water  bearing. 

Water  drawn  from  sandstone  is  always  well  filtered. 

The  amount  of  water  which  could  be  obtained  from 
sandstone  formations  in  some  parts  of  the  country  with 
sufficiently  extended  works  is  very  great  indeed,  and  the 
water  is  of  the  greatest  value  for  small  supplies.  For 
large  supplies,  the  limited  amount  that  can  usually  be 
drawn  regularly  by  one  pumping  station  is  a  serious  ob- 
stacle. The  multiplication  of  small,  scattered  pumping 
stations  may  often  involve  a  larger  outlay  than  the  cost 
of  securing  good  water  in  other  ways. 


48  GROUND  WATER  SUPPLIES. 

It  very  rarely  happens  that  over  3,000,000  gallons  of 
water  per  day  are  handled  from  one  pumping  station, 
either  from  sand  or  from  sandstone.  The  capacities  of 
by  far  the  greater  number  of  such  sources  will  be  fully 
reached  with  much  lower  drafts,  often  with  as  little  as 
1,000,000  gallons  per  day,  or  even  less. 

Limestone  Water.  Bethlehem,  Pa.,  is  not  a  large  city 
but  it  is  an  old  one,  and  it  was  one  of  the  first  in  this 
country  to  have  a  public  water  supply.  This  supply 
was  from  a  spring  coming  through  a  crevice  in  the 
limestone  rock.  The  spring  is  one  of  the  outlets  for  the 
drainage  of  a  considerable  area  near  the  city  and  higher 
than  it.  The  underground  flow  of  the  water  is  not 
through  the  porous  rock,  for  limestone  is  not  porous.  It 
is  through  fissures  or  passages.  These  are  called  caverns 
if  they  are  large  enough  and  are  accessible.  Such  fis- 
sures or  passages  exist  in  most  limestone  formations. 
They  are  the  natural  seams  or  cracks  enlarged  by  the 
gradual  solution  and  removal  of  the  rock  by  the  passing 
water.  Limestone  is  the  only  common  rock  that  is 
soluble  in  this  way,  and,  for  water  supply  purposes,  lime- 
stone formations  must  be  distinguished  from  all  others. 

As  the  crevices  may  be,  and  often  are,  continuous  for 
many  miles,  and  as  they  are  large  enough  so  that  large 
quantities  of  water  can  flow  through  them,  it  often  hap- 
pens that  quantities  of  water,  many  times  greater  than 
are  ever  obtainable  from  sandstone,  are  to  be  secured 
from  limestone.  On  the  other  hand,  as  limestone  is  not 
porous,  except  for  the  open  passages,  there  is  but  little 
storage  in  a  limestone  country.  That  is  to  say,  there  is 
but  little  ability  to  hold  the  abundant  winter  flows  to 


LIMESTONE  WATERS.  49 

maintain  the  supply  through  summer  droughts.  The 
difference  between  limestone  and  sandstone  in  this 
respect  is  striking.  While  much  more  water  is  frequently 
available  at  one  point  in  limestone,  the  amount  is  sub- 
ject to  greater  fluctuations,  and  the  supply  may  fall  short 
when  most  needed. 

San  Antonio,  Texas  (pop.  96,614),  is  supplied  with 
water  from  limestone  springs  flowing  in  great  volume. 
For  a  long  time,  until  the  city  grew  to  be  too  large,  the 
flow  was  sufficient  to  furnish  water  power  on  a  moderate 
fall  just  below  the  springs,  to  pump  the  water  required  to 
supply  the  city  to  an  elevated  reservoir. 

Wells  drilled  in  ^limestone  rock,  if  they  strike  large 
and  extended  passages,  often  yield  water  freely.  Such 
wells  may  drain  the  material  over  the  limestone  for  miles. 
If  that  material  happens  to  be  clayey  or  impervious,  the 
yield  will  be  less. 

Indianapolis  was  at  one  time  supplied  from  wells  in 
limestone,  and  Winnipeg  in  Canada  is  still  so  supplied. 
In  both  cases  the  amounts  obtainable  were  too  small  to 
allow  continued  dependence  on  these  supplies. 

Limestone  waters  are  not  well  filtered.  To  a  large 
extent  they  are  subject  to  pollution  from  the  entrance  of 
whatever  polluting  materials  there  may  be  on  the  tribu- 
tary areas.  Paris,  France,  partially  supplied  with  lime- 
stone water,  has  been  much  troubled  by  such  pollution. 
The  water  was  for  many  years  believed  to  be  pure,  but 
more  recent  investigations  have  made  it  clear  that  at 
least  a  considerable  part  of  the  excessive  amount  of 
typhoid  fever  long  prevalent  in  the  French  capital  has 
been  caused  by  this  water. 


50  GROUND  WATER  SUPPLIES. 

Vienna  has  been  more  fortunate,  but  this  is  because  the 
catchment  area  supplying  the  wonderful  "Kaiser  Brun- 
nen,"  and  the  other  limestone  sources  largely  supplying 
the  city,  are  all  in  the  high  mountains,  where  there  is 
scarcely  any  population  or  pollution.  For  these  sup- 
plies the  storage  question  is  supplied  in  a  most  unusual 
way,  namely,  by  means  of  ice  and  snow.  The  high 
mountains  are  snow-capped,  and  the  melting  snow  in 
summer  replenishes  the  springs,  so  that  the  summer  dis- 
charges are  greater  than  the  winter  ones. 

In  general,  limestone  supplies  are  of  inferior  sanitary 
quality.  Typhoid  fever  has  been  caused  by  their  use  rather 
frequently.  Such  cases  have  been  investigated  repeatedly 
and  thoroughly  in  Germany,  Switzerland,  France,  and 
England,  and  less  frequently  in  the  United  States. 

Sandstones  and  limestones  are  the  only  rocks  impor- 
tant as  sources  of  underground  water.  Artesian  wells 
are  sometimes  sunk  in  other  rocks,  and  occasionally 
water  is  secured.  This  happens  where  the  well  strikes 
an  open  seam,  which  serves  as  a  passageway  for  water 
entering  it  from  pervious  overlying  material.  Wells  of 
this  kind  seldom  yield  enough  water  for  public  supplies, 
even  in  small  towns,  though  supplies  for  private  resi- 
dences, small  hotels,  and  mills,  are  not  infrequently 
obtained  in  this  way. 

Hardness  of  Ground  Waters.  Ground  waters  are  apt 
to  be  hard;  that  is  to  say,  they  contain  large  amounts 
of  lime  and  magnesia  in  solution.  This  tends  to  make 
them  less  desirable  for  public  water  supplies.  Fre- 
quently, however,  this  is  not  a  controlling  consideration, 
although  always  an  important  one. 


HARDNESS  OF  GROUND  WATERS.  $1 

Two  conditions  must  be  present  to  make  a  ground 
water  hard.  First,  the  material  through  which  the  water 
passes,  or  some  of  it,  must  contain  the  hardness-produc- 
ing material,  and  second,  the  conditions  must  be  favor- 
able for  dissolving  it.  The  latter  practically  means  that 
carbonic  acid  must  be  present. 

The  waters  from  the  gravels  at  Brooklyn  and  Camden 
and  Lowell  are  soft,  because  the  gravels  contain  but 
little  lime,  and  that  little  is  not  in  a  soluble  condition. 
Sand  and  gravel  free  from  lime  are  common  in  New 
England,  parts  of  New  York  and  New  Jersey,  and 
generally  along  the  Atlantic  coast  to  the  southward. 

On  the  other  hand,  the  sands  and  gravels  of  central 
New  York,  and  westward  to  Minnesota  and  beyond, 
contain  lime  in  considerable  quantities,  and  waters 
drawn  from  them  are  hard. 

Different  waters  drawn  from  lime-containing  materials 
vary  greatly  in  hardness.  Generally  the  hardness  of  the 
water  does  not  depend  upon  the  amount  of  lime  in 
the  material  through  which  it  has  passed,  but  upon  the 
power  of  the  water  to  dissolve  the  lime.  If  any  lime 
at  all  is  present  in  form  to  be  dissolved,  there  is  pretty 
sure  to  be  enough  of  it  to  render  the  water  extremely 
hard  if  carbonic  acid  is  present  in  the  water  to  take 
it  up. 

Rain  water  contains  but  little  carbonic  acid,  and  has 
therefore  but  little  power  of  dissolving  lime,  and  so  of 
becoming  hard  while  passing  calcareous  materials.  The 
principal  source  of  the  carbonic  acid  required  to  enable 
the  water  to  dissolve  lime  is  the  soil.  The  soil  contains 
organic  matter  in  the  shape  of  roots,  humus,  etc.  Some 


52  GROUND  WATER  SUPPLIES. 

of  these  matters  are  decaying  and  becoming  oxidized 
with  the  formation  of  carbonic  acid.  The  rain  falls 
on  the  soil,  penetrates  it,  and  becomes  charged  with 
carbonic  acid.  Then  it  passes  to  the  calcareous  sand 
or  other  material  below,  and  lime  from  it  is  dissolved 
to  the  extent  of  the  dissolving  power  of  the  carbonic 
acid. 

The  hardness  of  the  water  therefore  depends  more 
upon  the  richness  or  fertility  of  the  soil  upon  the  catch- 
ment area  than  upon  the  amount  of  lime  in  the  various 
materials  through  which  the  water  flows,  provided  of 
course  that  there  is  some  substantial  amount  of  lime  to 
be  taken  up  where  conditions  permit. 

The  water  supply  of  Vienna  is  for  this  reason  compar- 
atively soft,  notwithstanding  that  it  comes  entirely  from 
limestone  rocks.  The  gathering  ground  is  barren  and 
sterile,  and  the  water  never  gets  the  carbonic  acid  needed 
to  dissolve  a  large  amount  of  lime.  In  a  sand-hill  region, 
where  the  sand  is  calcareous,  the  ground  water  will  be 
only  moderately  hard,  because  of  the  barrenness  of  the 
soil.  With  better  soil,  the  water  will  be  harder,  until 
with  an  extremely  rich,  fertile  soil  over  limestone,  as  at 
Winnipeg,  Canada,  water  of  the  very  greatest  hardness 
is  found. 

Iron  in  Ground  Water.  After  hardness  there  is  no 
question  of  greater  importance  in  considering  the  quality 
of  ground  waters  than  the  presence  of  iron.  Iron  is 
very  widely  distributed,  and  practically  all  the  'sands, 
gravels,  soils,  and  rocks  with  which  water  comes  in  con- 
tact, from  the  time  it  strikes  the  soil  as  rain  water  until  it 
emerges  to  the  spring  or  well,  contain  it.  Sometimes  the 


IRON  IN  GROUND  WATER.  53 

conditions  are  not  such  as  to  result  in  the  solution  of  the 
iron,  but  frequently  an  objectionable  amount  of  it  is 
taken  into  solution. 

When  iron  is  present  in  water  it  supports  the  growth 
of  crenothrix,  an  organism  which  grows  in  the  pipes  and 
which  is  extremely  troublesome.  And  it  further  sepa- 
rates, forming  a  red  precipitate  which  is  offensive  in 
appearance  and  is  dirty  in  tanks  and  wherever  the  water 
is  stored.  Water  containing  iron  also  discolors  and 
spoils  linen  and  other  fabrics  washed  in  it. 

The  solution  of  iron  from  the  soil  is  brought  about  by 
organic  matter.  This  takes  oxygen  away  from  the  iron 
of  the  soil,  reducing  it  from  the  ferric  to  the  ferrous 
state.  In  the  ferrous  state  the  iron  is  soluble  in  water 
containing  carbonic  acid,  and  trouble  from  iron  is 
always  to  be  expected  where  there  is  an  excess  of 
organic  matter  in  the  material  through  which  the  water 
passes. 

The  organic  matter  may  come  with  the  water  itself,  in 
case  of  seepage  from  a  dirty  and  polluted  river;  or  it  may 
be  present  in  the  soil.  Rain  water  does  not  contain  much 
organic  matter,  but  the  soil  on  which  it  falls  is  usually  rich 
in  it.  In  a  well  drained,  pervious  soil  the  oxygen  from 
the  air  circulates  in  the  pores  of  the  soil  and  furnishes 
what  is  required  by  the  organic  matter.  Iron  will  not 
be  dissolved  under  these  conditions,  even  in  presence  of 
large  amounts  of  organic  matter.  But  if  the  air  supply 
is  cut  off,  as,  for  instance,  in  case  the  pores  of  the  soil  are 
filled  with  water  by  flooding  or  saturation,  the  solution 
of  iron  is  sure  to  take  place. 

Iron  can  be  removed  from  ground  water  by  a  suitable 


54  GROUND  WATEK  SUPPLIES. 

method  of  purification,  and  such  removal  has  made  pos- 
sible the  utilization  of  many  valuable  sources  of  supply 
that  otherwise  could  not  have  been  used. 

The  ground  waters  of  northern  Germany  very  com- 
monly contain  iron.  Twenty  years  ago  Berlin  put  down 
many  wells  and  works  for  securing  ground  water,  the 
conditions  in  the  neighborhood  of  that  city  being  excep- 
tionally favorable.  But  after  a  short  period  of  use  the 
wells  were  abandoned  because  of  the  iron  in  the  water 
which  made  the  water  objectionable.  At  that  time  it 
was  not  known  how  to  remove  the  iron.  Afterward 
methods  of  iron  removal  were  discovered  and  used  in 
other  German  cities,  and  finally  in  the  last  years  the  old 
Berlin  well  water  supplies  have  been  gradually  brought 
back  into  service  and  extended,  but  this  time  with  the 
complete  artificial  removal  of  the  iron  from  the  water. 
And  this  water  is  gradually  supplanting  the  filtered  river 
water  which  otherwise  has  been  used  to  supply  the  city. 

All  these  German  iron-containing  waters  are  from 
deposits  of  silicious  sand,  in  a  general  way,  similar  to  that 
from  which  the  Brooklyn,  Lowell,  and  Camden  supplies 
are  obtained. 

Of  the  American  ground  water  supplies,  a  consider- 
able proportion  suffer  from  iron,  and  a  number  of  works 
for  iron  removal  are  in  use,  though  not  for  the  larger 
supplies.  As  far  as  known,  the  Camden  supply  has  not 
suffered  from  iron.  At  Lowell,  the  iron  is  more  or  less 
troublesome.  The  Brooklyn  wells  are  very  variable, 
according  to  location.  Some  are  free  from  iron.  Others 
have  so  much  that  the  unmixed  water  from  individual 
wells  would  not  be  usable.  But  when  it  is  all  mixed  in 


IRON  IN  GROUND  WATER.  55 

the  conduit,  including  large  amounts  of  surface  water, 
the  iron  is  not  present  in  large  enough  amounts  to  be  very 
troublesome.  It  is  noticed,  however,  and  is  an  unde- 
sirable element  in  the  supply. 

Superior,  Wis.,  Far  Rockaway,  N.  Y.,  and  Asbury 
Park,  N.  J.,  are  among  the  most  important  and  best 
known  places  in  the  United  States,  where  the  iron  in 
ground  water  supplies  has  compelled  the  construction 
of  works  for  its  removal. 

Manganese  also  occurs  in  ground  waters  occasionally. 
Manganese  is  a  metal  similar  in  many  ways  to  iron,  and 
is  the  basis  of  the  "spiegeleisen,"  used  in  making  steel. 
It  is  less  widely  distributed  in  nature  than  iron.  When 
it  is  present  in  the  soil  it  dissolves  under  the  same  con- 
ditions that  lead  to  the  solution  of  iron.  It  is  equally 
troublesome  to  the  users  of  the  water,  and  is  much  more 
difficult  to  remove  by  artificial  purification. 

Breslau,  Germany,  has  suffered  from  manganese  as 
well  as  from  iron,  and  part  of  the  recently  constructed 
ground  water  supply  works  have  been  abandoned  because 
of  it. 

As  far  as  known  manganese  has  not  been  troublesome 
in  any  very  large  public  supply  in  America,  but  it  has 
proved  most  objectionable  in  a  few  small  ones,  and  in 
some  mill  supplies. 

It  is  much  more  difficult  to  test  water  for  manganese 
than  for  iron,  and  but  few  chemists  have  looked  for  it 
adequately.  It  is  therefore  possible  that  full  investi- 
gation will  show  a  wider  distribution  of  manganese  in 
American  waters  than  is  now  recognized,  and  that  some 


56  GROUND  WATER  SUPPLIES. 

troubles  with  water,  the  causes  of  which  are  not  now 
understood,  may  be  attributed  to  this  metal. 

Sea  Water  in  Ground  Water  Supplies.  Many  impor- 
tant supplies  are  drawn  from  wells  near  the  ocean.  The 
Brooklyn  supply  is  so  located,  also  the  Far  Rockaway 
supply,  and  the  supplies  for  Staten  Island  and  Asbury 
Park,  and  many  small  places  along  the  New  Jersey  coast. 
The  supplies  of  The  Hague  and  Amsterdam  in  Holland 
are  also  obtained  close  to  the  coast.  In  all  these  cases 
the  presence  of  sea  water  in  the  wells  is  an  important 
matter.  In  many  cases  trouble  has  already  been  experi- 
enced. In  others  there  would  be  trouble  if  care  was  not 
exercised  to  prevent  it. 

The  admixture  of  even  a  small  proportion  of  sea 
water  renders  the  water  hard  and  salty  and  undesirable 
for  domestic  use.  The  magnesium  chloride  also  ren- 
ders such  water  unsuitable  for  use  in  boilers.  The  pas- 
sage of  sea  water  through  the  sand  between  the  sea  and 
the  wells  does  not  remove  the  salt  of  the  sea  water,  or 
even  reduce  it  in  the  slightest  degree. 

In  most  of  the  supplies  above  mentioned  the  fresh 
water  resulting  from  the  rainfall  upon  the  sandy  areas 
near  the  coast  naturally  reaches  the  sea  through  the 
sand  below  the  water  level.  Its  discharge  accounts 
for  the  springs  and  quicksands  often  noticed  on  the 
beach  at  low  tide.  Little  or  none  of  this  water  naturally 
comes  to  the  surface  of  the  ground  before  reaching  the 
sea. 

It  is  a  difficult  matter  to  draw  to  wells  or  galleries  all 
the  fresh  water  that  would  otherwise  flow  to  the  ocean, 


SEA  WATER  IN  GROUND  WATER  SUPPLIES.     57 

without  at  the  same  time  drawing  some  salt  water  to  the 
wells.  In  fact,  it  is  not  possible  to  do  this  perfectly.  It 
is  an  interesting  and  difficult  problem  to  so  arrange  and 
operate  the  works  as  to  get  the  maximum  quantity  of 
fresh  water  without  drawing  sea  water. 

The  problem  is  complicated  by  a  fairly  strong  ten- 
dency, due  to  the  difference  in  specific  gravity,  for 
sea  water  to  flow  back  under  the  land  in  the  sand 
below  the  surface,  when  the  water  level  at  a  distance 
back  from  the  shore  is  lowered  by  drawing  upon  the 
wells;  and  this  underflow  of  salt  water  may  take  place 
while  there  is  still  a  surface  flow  of  fresh  water  to  the 
ocean. 

When  sea  water  passes  back  under  the  wells  in  this 
manner  it  is  sure  to  become  mixed  with  the  fresh  water 
above  it  in  the  wells  sooner  or  later.  The  process  of  mix- 
ing is  constantly  taking  place  from  the  first  moment  that 
sea  water  begins  to  flow  into  the  land,  and  by  the  time 
that  sea  water  is  first  detected  in  the  wells,  large  amounts 
of  sea  water  may  be  in  the  sand  below  them,  and  it  may 
then  be  a  slow,  hard  process  to  operate  the  wells  so  as  to 
avoid  drawing  sea  water. 

It  is  clear  that  for  a  time  an  amount  of  fresh  water 
largely  in  excess  of  the  yield  that  can  be  permanently 
maintained  can  be  drawn  from  such  wells,  the  excess 
amount  being  taken  from  the  sand,  and  its  space  being 
gradually  taken  by  salt  water.  For  this  reason  the 
amount  of  water  which  can  be  permanently  maintained 
from  such  works  is  much  more  difficult  to  determine,  and 
in  fact  can  only  be  determined  by  experience  extending 


$8  GROUND  WATER  SUPPLIES. 

over  a  far  longer  period  than  is  required  to  establish  the 
yield  of  wells  not  so  situated. 

This  sea  water  question  has  been  more  thoroughly  and 
scientifically  studied  in  Holland  than  elsewhere.  The 
Dutch  literature  upon  this  subject  is  most  important,  and 
many  of  the  methods  of  studying  conditions  and  of  regu- 
lating the  supply  that  are  there  used  may  be  adopted 
elsewhere  with  advantage. 


CHAPTER  VI. 

ON  THE  ACTION  OF  WATER  ON  IRON  PIPES 

AND  THE  EFFECT  THEREOF  ON  THE 

QUALITY  OF  THE  WATER. 

IT  is  well  known  that  nearly  all  waters  attack  iron  pipes, 
corroding  them  and  forming  tubercles  on  the  inner  sur- 
face. The  rates  at  which  this  corrosion  and  tubercu- 
lation  take  place  with  different  waters  and  different 
kinds  of  pipe  have  been  studied  by  many  engineers  at 
length.  It  has  been  studied  almost  entirely  from  the 
point  of  view  of  the  reduction  of  carrying  capacity  of  the 
pipe,  and  hardly  at  all  from  the  standpoint  of  the  effect 
upon  the  quality  of  the  water.  The  latter  seems  to  be 
a  matter  of  considerable  importance,  however. 

The  way  that  the  process  of  tuberculation  goes  for- 
ward seems  to  be  something  like  this :  The  water  flowing, 
at  times  slowly,  and  carrying  matters  in  suspension,  de- 
posits some  of  these  suspended  matters  on  the  lower  half 
of  the  pipe.  This  deposit  usually  contains  a  consider- 
able amount  of  organic  matter. 

The  iron  pipe  is  coated  with  tar  or  asphalt.  If  this 
coating  were  perfect  and  complete,  the  deposit  would  not 
come  in  contact  with  the  iron  at  any  point.  But  there 
are  always  blow-holes  or  other  minute  openings  in  the 
coating,  and  it  is  through  these  that  the  iron  is  first 
reached. 

59 


60  ACTION  OF  WATER  ON  IRON  PIPES. 

The  organic  matters  in  the  deposit  over  the  iron  are  in 
a  state  of  decomposition;  that  is  to  say,  they  are  rotting. 
This  results  in  the  generation  of  carbonic  acid.  The 
carbonic  acid  acts  on  the  iron  through  the  openings  in 
the  pipe  coating.  It  takes  some  of  this  iron  into  solution 
as  ferrous  carbonate.  The  soluble  ferrous  carbonate 
diffuses  through  the  water,  penetrating  the  deposit  under 
which  it  is  formed,  and  reaching  the  upper  surface  of  it, 
where  it  comes  in  contact  with  the  water  flowing  in  the 
pipe.  A  part  of  the  iron  mingles  with  the  water  in  the 
pipe  and  goes  forward  with  it.  Another  part,  becoming 
oxidized  by  the  oxygen  in  the  flowing  water,  is  trans- 
formed to  the  insoluble  ferric  condition  and  remains  at 
the  surface  of  the  deposit. 

The  iron  precipitated  in  this  way  acts  as  a  coagulant. 
It  coagulates  some  of  the  organic  matter  in  the  flowing 
water  at  the  point  where  the  iron  is  precipitated.  It 
binds  the  organic  matter  so  precipitated,  and  that 
previously  deposited,  into  a  firm,  compact,  but  porous 
mass,  and  this  mass  is  the  beginning  of  a  tubercle. 

The  organic  matter  precipitated  by  the  iron  at  the 
surface  of  the  tubercle  is  so  much  fuel  added  to  the  flame 
of  decomposition,  and  the  carbonic  acid  resulting  from 
it  leads  to  the  solution  of  further  quantities  of  iron.  In 
this  way  the  process  becomes  a  continuous  one. 

The  circulation  of  the  liquid  through  the  tubercles, 
taking  the  carbonic  acid  to  the  iron  and  bringing  the  iron 
to  the  surface,  is  very  slow,  and  many  years  may  elapse 
before  the  tubercle  reaches  the  height  of  an  inch. 

Tuberculation  is  practically  universal  in  cast  iron 
water  pipes,  but  some  waters  cause  the  action  to  go  for- 


Tubercles  Growing  in  Iron  Water-pipes. 
Courtesy  of  Prof.  Gardner  S.  Williams. 


TtJBERCULATION.  6l 

ward  much  more  rapidly  than  others.  Tuberculation 
starts  much  more  freely,  and  progresses  more  rapidly, 
in  waters  from  rivers  or  reservoirs  containing  suspended 
organic  matters.  It  is  less  troublesome  with  filtered 
waters  and  with  lake  waters  relatively  free  from  such 
suspended  matters.  Pipes  carrying  river  waters  con- 
taining much  inorganic  sediment,  that  is  to  say,  clay  and 
silt,  and  having  but  little  organic  sediment,  are  less  likely 
to  become  tuberculated  than  those  carrying  waters  with 
organic  sediment. 

The  difference  between  the  action  of  raw  water  and 
filtered  water  upon  pipes  is  very  striking  in  the  piping 
about  filter  plants.  The  tubercles  in  the  raw  water  pipes 
are  found  to  be  much  more  numerous  and  larger  than 
those  in  the  filtered  water  pipes. 

The  character  of  the  tar  or  asphalt  pipe  coating  also 
has  a  great  deal  to  do  with  tuberculation.  The  coal-tar 
dip  is  still  used  for  cast-iron  pipe  and  sometimes  for  steel 
pipe,  and  on  the  whole  has  stood  the  test  of  time  as  well 
or  better  than  many  of  the  improved  coatings  that  have 
often  replaced  it. 

The  cement  lined  pipes,  extensively  used  years  ago, 
and  now  abandoned  in  water  works  practice  because  of 
defects  in  other  particulars,  were  not  subject  to  tubercu- 
lation, and  had  this  distinct  advantage  over  the  cast  iron, 
pipes  which  have  displaced  them. 

The  effect  of  tuberculation  in  increasing  the  frictional 
resistance  of  water  in  pipes,  or,  what  is  the  same  thing,  of 
decreasing  the  flow  through  them,  is  well  known.  It  is 
common  to  find  that  twice  as  much  head  is  required  to 
carry  a  given  quantity  of  water  through  a  pipe  after 
twenty  years  of  use  as  when  the  pipe  was  new. 


62  ACTION  OF  WATER  ON  IRON  PIPES. 

Pipe  scrapers  have  been  sometimes  used  to  remove 
tubercles.  They  consist  of  appliances  driven  by  the 
water  pressure  through  the  pipes  with  arrangements  to 
scrape  off  the  tubercles.  Scraping  in  this  way  has  the 
effect  of  restoring  to  a  considerable  extent  the  original 
carrying  capacity  of  the  pipe.  The  process,  to  remain 
effective,  must  be  repeated  at  intervals,  and  when  so  re- 
peated it  has  the  effect  of  removing  a  large  part  of  the 
tar  coating  and  leaving  the  iron  of  the  pipe  exposed  to  the 
action  of  the  water  to  a  much  greater  extent  than  would 
have  been  the  case  without  scraping. 

The  iron  that  is  oxidized  and  dissolved  as  a  result  of 
the  process  of  tuberculation  is,  in  considerable  part,  pre- 
cipitated at  the  surface  of  the  tubercles,  and  it  forms  the 
cementing  material  which  makes  them  possible.  But 
only  a  part  of  the  iron  is  thus  precipitated;  the  rest  goes 
forward  with  the  flowing  water.  At  first  it  is  in  a  state 
of  solution,  but  the  dissolved  oxygen  in  the  water  oxi- 
dizes it  slowly  to  the  ferric  or  insoluble  state. 

If  the  water  contains  much  organic  matter  in  solution 
this  may  prevent  the  precipitation  of  the  iron.  In  this 
case  it  increases  the  color  of  the  water.  It  is  able  to  do 
this  only  where  the  amount  of  iron  in  proportion  to  the 
organic  matter  is  comparatively  small.  This  is  usually 
the  case  with  dirty  river  and  reservoir  waters.  If  there 
is  not  sufficient  organic  matter  in  the  water  to  hold  the 
iron  in  solution,  it  will  separate  out  after  oxidation  and 
will  deposit  where  the  flow  in  the  pipes  is  slow.  This  is 
usually  the  case  with  filtered  water  and  other  waters  of 
organic  purity. 

That  part  of  the  water  which  goes  through  the  water- 


PRECIPITATION  OF  IRON.  63 

backs  of  the  kitchen  stoves  to  the  hot- water  tanks  is  par- 
ticularly likely  to  have  its  iron  separated,  and  the  iron  so 
separated  usually  accumulates  on  the  bottoms  of  the  hot- 
water  tanks.  The  iron  separating  from  the  water  in 
this  way  is  not  likely  to  be  drawn  at  all  times.  It  is  far 
more  likely  to  accumulate  in  pipes  and  tanks  for  days 
or  even  for  weeks,  until  sometime,  with  an  unusually 
rapid  draft  of  water  or  other  disturbance,  perhaps  on 
washing-day,  the  iron  which  has  accumulated  for  days 
or  weeks  is  all  flushed  out  in  a  limited  quantity  of 
water.  Then  the  superintendent  of  the  water  works 
hears  from  it. 

This  intermittent  appearance  of  iron  is  one  of  the 
characteristic  features  of  iron  troubles  from  ground 
water,  and  the  presence  of  iron  is  much  more  objection- 
able to  the  takers  of  the  water  than  it  would  be  if  it  was 
more  uniformly  distributed  through  the  water. 

The  solution  and  subsequent  precipitation  of  iron  in 
this  way  seems  to  be  more  or  less  universal  in  connection 
with  iron  water  pipes.  The  tendency  of  this  action  is 
to  make  a  surface  water  behave  like  a  ground  water 
naturally  containing  iron,  and  all  the  disagreeable 
features  of  an  iron-containing  ground  water  may  be 
produced  in  greater  or  less  degree  as  a  result  of  these 
actions. 

Where  water  is  taken  from  a  source  that  is  recognized 
to  be  dirty,  as,  for  instance,  from  a  turbid  river  or  from  a 
reservoir  with  vegetable  growths,  the  public  is  pretty 
sure  to  take  these  phenomena  as  representing  a  part  of 
the  natural  dirtiness  of  the  source.  There  are  cases 
where  the  uncleanness  popularly  attributed  to  the  water 


64  ACTION  OF  WATER  ON  IRON  PIPES. 

of  the  source  is  really  attributable  in  greater  measure  to 
the  iron  taken  up  from  the  pipes. 

For  this  reason  it  seldom  happens  that  the  action  of 
the  iron  pipes  in  increasing  the  dirty  appearance  of  the 
water  is  recognized  as  long  as  the  source  of  supply  has  a 
bad  reputation.  When  a  filter  plant  is  installed,  or  clean 
water  from  a  new  source  is  secured  in  place  of  a  dirty 
one,  then  the  effect  of  the  iron  commences  to  be  noticed 
and  to  receive  serious  attention.  It  is  found  that  water 
leaving  a  filter  plant  or  entering  the  pipes  from  a  new 
reservoir,  is  bright,  colorless,  and  free  from  iron.  As 
drawn  from  the  taps  to  the  consumers  it  is  discolored 
and  comes  out  a  milky  yellow  or  reddish,  according  to 
the  amount  of  iron  present.  This  color  comes  intermit- 
tently, and  between  the  dirty  spells  there  are  times  when 
clean  water  is  drawn.  The  people  get  used  to  the 
appearance  of  clean  water,  and  quickly  notice  the  differ- 
ence when  the  iron  comes,  and  they  are  troubled  by  it. 
Often  they  believe  that  the  filter  has  gone  wrong,  or  some 
unreported  source  of  pollution  is  reaching  the  water. 

Sometimes  the  matter  is  aggravated  by  a  softening  by 
chemical  action  and  loosening  of  old  deposits  in  the 
pipes  which  follows  a  change  in  the  character  of  the 
water  supply.  When  this  is  the  case,  repeated  and  ade- 
quate flushings  of  the  pipe  will  considerably  improve 
the  situation. 

To  make  flushing  effective  it  is  necessary  to  shut  off 
all  side  pipes  and  open  the  hydrants  at  the  end  of  each 
line  of  pipe,  so  as  to  produce  through  that  line  for  a  few 
minutes  a  velocity  many  times  greater  than  any  that  is 
possible  in  ordinary  use. 


FLUSHING  PIPES.  65 

Flushing  must  be  done  in  this  way  to  be  effective, 
and  opening  hydrants  here  and  there  throughout  a  city, 
without  closing  the  gates  necessary  to  concentrate  the 
flow,  simply  has  the  effect  of  stirring  up  the  old  deposits 
in  the  pipe,  and  of  mixing  them  with  the  water,  and  of 
producing  unnecessarily  bad  water  without  effectively 
removing  the  source  of  trouble. 

This  deterioration  of  water  as  a  result  of  contact  with 
iron  pipes,  and  especially  of  old  pipes  containing  large 
numbers  of  growing  tubercles,  is  one  of  the  most  trouble- 
some ones  in  connection  with  securing  clean  waters  and 
of  supplying  them  through  pipes  long  used  for  carrying 
dirty  water. 

The  troubles  resulting  from  it  are  important,  even 
though  not  of  equal  importance  to  sanitary  quality  or  to 
turbidity  and  color.  Water  is  never  less  wholesome 
because  of  iron,  but  it  is  less  attractive  in  appearance, 
and  the  difference  is  clearly  noticed  by  the  public. 

The  tubercles  that  grow  in  water  pipes  are  very  good 
friends  to  the  men  who  sell  spring  water.  They  also  do 
a  great  deal  to  make  possible  the  business  of  supplying 
domestic  filters. 

Domestic  filters  are  not  in  general  a  very  sure  means 
of  removing  disease-producing  qualities  from  polluted 
waters.  There  are  too  many  uncertainties  connected 
with  their  operation  to  make  them  reliable  in  this 
respect.  But  the  iron  that  comes  from  the  pipes  is 
very  easily  removed  by  such  filters,  and  good  domestic 
filters  furnish  the  most  convenient  and  satisfactory  means 
of  removing  such  deposits  from  water  that  is  otherwise 
good. 


66  ACTION  OF  WATER  ON  IRON  PIPES. 

Probably  if  new  pipes  should  be  provided  in  place  of 
the  old  ones,  when  clean  water  is  secured  at  the  source; 
and  if  better  coatings  could  be  used,  relatively  little  trou- 
ble would  be  experienced  from  iron.  But  the  old  water 
pipes  are  in  use,  and  they  represent  large  investments  and 
cannot  be  changed  for  a  matter  of  secondary  importance. 

It  is  to  be  hoped  that  a  study  of  this  subject  and  a 
recognition  of  its  importance  will  result  in  time  in  the 
use  of  better  pipe-coatings,  or  possibly  in  the  use  of  pipes 
presenting  to  the  water  some  surface  which  is  not  subject 
to  tuberculation. 

In  the  meantime,  managing  the  situation  by  flushing 
out  such  old  deposits  as  can  be  flushed  out,  by  explain- 
ing the  action  of  the  tubercles  to  those  citizens  who 
are  sure  that  the  water  is  bad  when  it  is  only  tempora- 
rily discolored,  and  generally  keeping  the  public  good- 
natured,  calls  for  the  greatest  skill  and  tact  on  the  part 
of  the  water  works  superintendent. 


CHAPTER  VII. 
RED-WATER  TROUBLES. 

THE  term  "  Red-water  Troubles "  has  come  to  be 
applied  to  conditions  of  the  general  character  described 
in  the  preceding  chapter,  where  the  amount  of  iron  in 
the  water  drawn  from  the  taps  of  the  consumers  has 
increased  to  a  point  to  be  generally  objectionable. 

Red-water  troubles  are  most  prevalent  with  very  soft, 
clean  waters.  They  are  less  frequent  with  harder  waters. 

The  pipes  employed  to  take  water  from  the  street 
mains  and  through  the  houses  have  been  found  to  play 
a  larger  part  in  the  red-water  problem  than  the  street 
mains.  Although  the  distance  that  the  water  passes 
through  these  service  and  plumbing  pipes  is  short,  it 
frequently  happens  that  more  iron  is  taken  up  from 
them  in  a  few  feet  than  from  the  miles  of  pipes  in  the 
streets  through  which  it  passed  before  reaching  them. 
The  red-water  troubles  result  from  the  total  amount  of 
iron  in  the  water  drawn;  and  it  makes  no  difference 
whether  it  came 'from  the  street  pipes  or  from  the 
plumbing. 

It  often  happens  that  a  little  iron  is  taken  up  from  the 
street  pipes,  but  not  enough  to  be  noticeable  by  itself. 
With  the  added  amount  from  the  service  pipes  the  total 
is  increased  until  it  is  noticeable,  and  the  amount  taken 

67 


68  RED-WATER  TROUBLES. 

from  the  street  pipes  is  thus  a  contributor  to  the  final 
result,  although  insufficient  alone  to  produce  it. 

The  corrosion  of  iron  in  the  hot- water  system,  other 
things  being  equal,  is  many  times  more  rapid  than  in 
the  cold-water  system,  and  it  takes  place  not  only  in  the 
pipes,  but  also  in  the  heaters,  hot-water  tanks  and 
wherever  water  meets  iron  in  the  hot-water  system. 
Red-water  troubles  are  therefor'much  more  common  and 
more  conspicuous  in  the  hot  water  than  in  the  cold 
water.  Frequently  they  are  confined  to  the  hot  water. 

Red-water  ^troubles  are  often  found  in  some  houses 
on  a  street  but  not  in  others.  The  difference  in  rapidity 
with  which  pipes  in  different  houses  corrode  is  often 
strikingly  great  and  difficult  to  explain. 

Formerly  lead  pipes  were  used  for  service  and  plumbing 
pipes  more  than  at  present.  Their  use  has  been  discon- 
tinued, in  many  cases  because  it  has  been  found  that 
certain  soft  waters  attack  the  lead  slowly,  taking  a  little 
of  it  into  solution,  and  tending  to  produce  lead  poisoning 
among  those  who  use  the  water.  Generally  speaking, 
the  waters  that  are  soft  enough  and  have  corrosive  power 
enough  to  attack  lead  are  also  the  waters  which  corrode 
iron,  and  with  which  red-water  troubles  are  experienced. 

Various  kinds  of  pipe  have  been  used  to  take  the  place 
of  lead  pipe,  but  galvanized  wrought-iron  pipe  has  been 
used  more  than  any  other.  The  zinc  of  the  galvanizing 
is  intended  to  protect  the  iron  from  corrosion,  and 
actually  it  does  so  to  a  certain  extent;  but  the  actions 
that  would  dissolve  the  iron  also  dissolve  the  zinc,  and 
sooner  or  later  the  protective  zinc  disappears  in  whole 
or  in  part  and  the  corrosion  of  the  iron  goes  forward. 


RED-WATER  TROUBLES.  69 

Steel  pipe  has  largely  replaced  wrought  iron  in  the 
last  decade,  and  in  keen  business  competition  the  quality 
of  the  pipe  has  been  reduced,  and  inadequate  methods 
of  galvanizing  have  been  used,  so  that  much  of  the  pipe 
actually  sold  has  been  of  a  kind  to  be  more  easily  corroded 
than  the  well-galvanized  wrought-iron  pipe  formerly 
used  and  still  to  be  obtained  at  an  increased  price. 

Poor  and  imperfectly  galvanized  pipe  has  been  one  of 
the  most  potent  causes  of  red-water  troubles,  as  is 
demonstrated  by  the  fact  that  in  almost  every  community 
where  red-water  troubles  exist  many  individual  houses 
will  be  found  using  galvanized-iron  pipe  where  no  trouble 
is  experienced.  Frequently  the  older  houses  have  given 
less  trouble  because  the  pipe  was  of  more  resistant  quality 
when  they  were  built,  while  the  newer  ones  have  suffered 
most. 

Since  the  discussion  of  red-water  troubles  in  the  last 
years  there  has  been  renewed  effort  to  secure  a  better 
grade  of  pipe,  and  this  is  no  doubt  being  gradually 
accomplished. 

Anything  that  increases  the  tendency  to  corrosive 
action  of  the  water  increases  the  likelihood  of  red-water 
troubles.  The  chemical  treatment  of  water  used  to  aid 
in  the  removal  of  color,  turbidity  and  other  matters 
has  been  often  carried  out  in  such  a  way  that  the  water 
supplied  was  more  corrosive  than  the  water  would  have 
been  without  the  treatment.  Apparently  with  very  soft 
water  and  a  short  period  of  coagulation  the  chemical 
reaction  taking  place  between  the  coagulant  and  the 
lime  in  the  water  does  not  have  time  to  be  completed 
before  the  water  goes  to  the  niters,  and  the  filtered  water 


70  RED-WATER  TROUBLES. 

acts  as  if  it  still  contained  some  slight  undecomposed 
residue  of  the  coagulant  with  its  corrosive  powers,  even 
though  the  water  carries  more  than  enough  lime  to 
complete  the  reaction. 

It  is  not,  however,  necessary  to  accept  this  view  to 
account  for  the  increased  corrosive  action  of  the  coagu- 
lated water.  The  reduced  alkalinity  and  the  increased 
carbonic  acid  resulting  from  the  coagulation  both  facili- 
tate corrosion;  and  the  change  in  the  water  in  these 
respects  as  a  result  of  the  coagulation  of  a  very  soft  and 
highly  colored  water  would  be  sufficient  to  make  an 
appreciable  difference  in  the  behavior  of  the  water  in  the 
pipes. 

Red-water  troubles  are  preventable.  It  may  not 
always  be  feasible  to  apply  remedies  sufficient  to  provide 
a  complete  cure,  but  they  can  always  be  reduced  to 
relatively  unimportant  proportions. 

Local  Remedies.  Brass  pipes  and  copper-storage  tanks 
should  be  used  exclusively  in  hot-water  systems  where  there 
is  a  tendency  to  red  water,  and  the  area  of  the  exposed 
iron  in  the  heaters  should  be  reduced  as  much  as  pos- 
sible. These  simple  measures  will  prevent  red-water 
troubles  in  the  hot-water  system  in  nearly  all  cases.  The « 
increased  cost  of  using  brass  in  new  houses  as  compared 
with  galvanized-steel  pipe  is  not  as  great  as  might  be  sup- 
posed, because  the  brass  pipe  is  smoother  and  carries 
more  water,  even  when  new,  and  is  not  subject  to  corro- 
sion with  the  accompanying  reduction  in  carrying  capacity 
when  old.  Brass  pipe  may  therefore  be  one  or  two 
sizes  smaller  without  sacrifice  of  capacity.  It  is  not 
necessary  to  use  any  pipe  more  than  half  an  inch  in 


GENERAL  TREATMENT.  71 

diameter  in  a  brass  hot-water  system  of  an  ordinary 
residence. 

For  the  cold-water  system  galvanized  pipe  may  be 
used,  but  it  should  be  from  a  responsible  manufacturer 
and  protected  by  an  adequate  coating  of  zinc,  and  should 
be  thoroughly  inspected  to  insure  its  quality. 

Generally  speaking,  the  red-water  troubles  are  worst 
in  houses  where  the  water  is  heated  very  hot.  We  have 
examples  of  this  in  apartment  houses,  where  the  water 
is  heated  in  special  heaters  in  the  cellar  and  in  houses 
where  it  is  heated  in  the  furnace.  A  temperature  of 
140°  is  sufficient  for  all  ordinary  uses  of  hot  water, 
and  to  exceed  this  only  invites  trouble.  Where  the  water 
is  heated  by  gas  it  is  possible  to  regulate  the  temperature 
of  the  hot  water. 

It  has  been  suggested  that  passing  the  heated  water 
into  an  open  tank  at  the  top  of  the  house  and  delivering 
the  supply  to  the  faucets  by  gravity  from  this  tank 
would  reduce  corrosion  by  permitting  some  of  the  dis- 
solved oxygen  to  escape.  Under  some  conditions  this 
might  be  worth  doing. 

These  local  remedies  will  serve  to  correct  the  worst 
of  the  red- water  troubles. 

General  Treatment.  In  addition,  it  may  be  desirable 
to  employ  some  general  remedy,  consisting  of  a  special 
chemical  treatment  of  the  water  to  reduce  its  corrosive 
power. 

Quicklime  is  probably  the  most  efficient  all-round 
material  to  be  added  to  water  for  this  purpose.  Its  use 
increases  the  alkalinity  and  reduces  the  free  carbonic 
acid.  It  increases  slightly  the  hardness  of  the  water; 


72  RED-WATER  TROUBLES. 

but  it  may  be  noted  that  the  treatment  is  only  desirable 
in  the  case  of  extremely  soft  waters;  and  in  these  cases 
the  relatively  slight  increase  in  hardness,  due  to  the 
addition  of  the  small  required  amount  of  lime,  may  not 
be  objectionable. 

Calcium  carbonate,  applied  in  the  form  of  an  insoluble 
powder,  has  been  used  in  England  to  harden  very  soft 
moorland  waters,  and  to  reduce  their  corrosive  power, 
especially  with  reference  to  bad  service  pipes.  It  takes 
twice  as  much  calcium  carbonate  to  take  up  a  given 
amount  of  carbonic  acid,  and  the  substance  being  an 
insoluble  powder  is  not  as  conveniently  and  easily  applied 
as  the  soluble  quicklime. 

Soda  ash  has  been  employed  to  increase  alkalinity 
and  reduce  carbonic  acid,  and  it  does  this  without  hard- 
ening the  water;  but  it  is  more  expensive  than  lime 
and  it  also  seems  to  be  less  efficient. 

The  use  of  the  lime  treatment  to  reduce  the  corrosive 
powers  of  waters  is  not  confined  to  waters  that  have  been 
coagulated.  Coagulation  only  increases  slightly  the 
previously  existing  tendencies,  and  these  tendencies  are 
frequently  so  great  as  to  warrant  corrective  treatment 
even  where  no  coagulant  is  applied.  Mr.  George  C. 
Whipple  l  has  suggested  the  advisability  of  the  use  of 
lime  with  all  exceedingly  soft  waters  to  decrease  the 
corrosion  of  the  pipes  and  improve  the  physical  character 
of  the  water  that  can  be  drawn  from  the  house  faucets. 

Journal  of  the  New  England  Water  Works  Association,  Vol.  27,  p. 
193- 


CHAPTER  VIII. 

DEVELOPMENT  OF  WATER  PURIFICATION 
IN  AMERICA. 

THE  filtration  of  river  waters  to  remove  sediment  and 
turbidity  and  other  impurities  has  been  practised  in 
Europe  for  many  years.  The  first  serious  American 
effort  in  this  direction  was  made  by  the  city  of  St.  Louis 
in  1866,  when  the  late  J.  P.  Kirkwood,  a  civil  engineer, 
was  sent  to  Europe  with  instructions  to  study  the  art 
and  apply  it  to  St.  Louis. 

Mr.  Kirkwood  made  a  report  upon  this  subject,  and 
a  general  plan  for  works  for  St.  Louis  based  upon  this 
study.  This  report  was  most  remarkable  for  the  in- 
sight shown  into  the  conditions  of  success  with  European 
waters,  and  it  will  always  remain  as  a  singularly  accu- 
rate statement  of  the  conditions  of  the  art  as  they  existed 
at  that  time. 

Kirkwood's  plan  for  filtering  the  St.  Louis  water 
was  not  adopted.  Possibly  the  cost  was  too  great  and 
the  benefits  of  purification  too  little  understood  at  that 
time;  but  there  is  some  reason  for  supposing  that  tests 
made  on  a  small  scale,  the  results  of  which  were  not 
made  public,  served  to  show  the  inadequacy  of  the  pro- 
posed plan.  However  that  may  be,  we  now  know  that 
the  plan  would  not  have  given  success,  and  that  no  plan 

73 


74  WATER  PURIFICATION  IN  AMERICA. 

based  on  European  experience  could  have  done  so. 
For  among  the  niters  of  Europe  there  was  not  one 
that  received  water  resembling  even  remotely  the  Mis- 
sissippi River  at  St.  Louis,  or  that  was  capable  of 
treating  such  water. 

Although  Kirkwood's  design  for  St.  Louis  was  never 
carried  out,  several  niters  were  built  by  other  cities  as  a 
result  of  his  work  and  report.  From  his  plans  a  filter 
was  built  for  Poughkeepsie,  N.  Y.  There  the  conditions 
were  sufficiently  like  those  of  European  filters;  and  the 
plant  was  the  first,  and  by  far  the  most  successful,  of  the 
early  water  purification  plants  in  this  country.  After- 
ward a  number  of  small  but  successful  plants  were  built 
upon  similar  lines.  Among  them  were  the  filters  at  Hud- 
son and  at  West  Point,  N.  Y.  (both  near  Poughkeepsie), 
and  at  St.  Johnsbury,  Vt. 

In  other  cases  success  was  not  attained.  Lowell, 
Columbus,  Toledo,  and  other  cities  also  copied  the  Pough- 
keepsie filters  more  or  less  closely  but  without  corres- 
ponding success.  These  failures  were  no  doubt  due  in 
some  cases  to  the  failure  to  provide  adequate  filtering 
area,  and  to  modifications  of  the  design  which  did  not 
prove  to  be  beneficial.  And  in  other  cases  they  were  due, 
or  partly  due,  to  the  fact  that  the  water  carried  more 
suspended  matter,  and  this  affected  the  process  to  such 
an  extent  that  the  general  method  was  not  applicable. 

Soon  after  this  the  late  Professor  William  Ripley 
Nichols  of  Boston  became  interested  in  filtration.  He 
made  experiments  with  it,  talked  of  its  application  to  the 
particular  problems  with  which  he  had  to  do,  and  wrote 
an  uncommonly  interesting  report  upon  the  subject  of 


HISTORICAL.  75 

water  purification  based,  like  Kirkwood's,  upon  Euro- 
pean experience. 

This  report  led  to  an  experimental  trial  by  the  late 
A.  Fteley,  then  engineer  of  the  Boston  water  works.  Other 
trials  were  made  at  Louisville  and  elsewhere.  These 
trials,  on  the  whole,  were  not  encouraging,  and  did  not 
lead  to  practical  applications  of  the  method. 

About  1884  the  beginnings  of  a  new  method  of  nitra- 
tion, destined  to  play  a  large  part  in  water  purification! 
made  their  appearance.  The  process  was  patented  by 
the  late  J.  W.  Hyatt,  and  the  late  Professor  Albert  R. 
Leeds  was  largely  interested  in  the  early  development 
of  the  invention. 

The  essential  and  characteristic  features  of  this  method 
were  the  addition  of  a  coagulant  or  chemical  precipi- 
tant to  the  water,  and  afterward  passing  it  through  a 
sand  layer  so  arranged  that  it  could  be  mechanically 
washed  by  a  reverse  current  of  water,  aided  some- 
times by  other  appliances.  These  features  are  char- 
acteristic, and  have  been  the  distinctive  features  of 
mechanical  filtration,  as  it  is  called,  to  the  present 
day. 

This  method  met  with  some  successes,  and  in  the 
decade  that  followed  quite  a  number  of  plants  were  in- 
stalled. These  were  divided  between  supplies  for  small 
cities,  and  supplies  for  paper  mills.  Paper  mills  require 
large  quantities  of  clean  water,  and  they  have  been  among 
the  earliest  and  best  patrons  of  those  who  had  methods 
of  purifying  water. 

The  Massachusetts  State  Board  of  Health  commenced 
to  investigate  the  purification  of  sewage  and  water  in 


76  WATER  PURIFICATION  IN  AMERICA. 

1887.  At  first  the  purification  of  sewage  received  most 
attention,  but  about  1890  the  study  of  water  purification 
was  taken  up  energetically.  And  this  experimental 
work  did  a  great  deal  to  develop  the  art  of  water  purifi- 
cation in  America. 

In  carrying  out  these  investigations  Merrimack  River 
water  only  was  used.  This  water,  which  was  used  by 
the  city  of  Lawrence  at  the  time,  contained  a  great  deal 
of  sewage,  and  caused  much  typhoid  fever  among  those 
who  used  it.  It  was  also  somewhat  colored,  but  was 
not  subject  to  much  turbidity.  It  was  in  a  general  way 
much  the  same  kind  of  water  that  had  been  successfully 
filtered  in  Europe  for  the  supply  of  such  cities  as  London, 
Berlin,  etc. 

These  experiments  were  carried  out  at  Lawrence, 
under  the  direction  of  Mr.  Hiram  F.  Mills,  with  at  first 
the  writer,  and  afterward  Mr.  George  W.  Fuller,  and  still 
later  Mr.  H.  W.  Clark,  in  direct  charge,  and  with  the  ad- 
vice of  the  late  Professor  Thomas  M.  Drown,  and  of  Pro- 
fessor William  T.  Sedgwick.  They  served  to  determine 
in  a  practical  way  the  nature  of  the  processes  that  were 
investigated,  and  to  show  the  conditions  of  success  with 
them  as  far  as  they  could  be  determined  by  small  experi- 
ments ;  and  the  results  obtained,  which  were  most  promis- 
ing and  were  duly  published,  served  to  interest  many 
people  in  water  purification. 

As  a  result  of  these  experiments  the  city  of  Lawrence 
built  a  sand  filter  to  purify  its  water  supply.  This  was 
designed  by  Mr.  Mills,  following  in  a  general  way,  but 
not  in  detail,  European  precedent,  for  it  was  based 
largely  upon  the  results  of  the  tests  made,  and  in  many 


Interior  of  a  Sand  Filter  at  Toronto,  showing  layer  of  dirty  sand 
removed  by  scraping. 


Interior  of  covered  pure-water  reservoir  at  Watertown,  N".  Y. 


-.»••*  «•        * 


rt^    &  o"    ^       v 


THE   LAWRENCE  FILTER.  77 

ways  it  was  quite  different  from  any  previous  construc- 
tion. This  filter  was  put  in  service  in  1893. 

The  Lawrence  filter  was  the  first  filter  built  in  America 
for  the  express  purpose  of  reducing  the  death  rate  of  the 
population  supplied,  and  it  accomplished  this  purpose 
in  a  most  striking  manner.  Comparing  the  five  years 
after  it  was  in  service,  with  five  years  before  it  was  in 
use,  there  was  a  reduction  of  79  per  cent  in  the  typhoid 
fever  death  rate,  which  had  been  excessive  for  many 
years.  No  less  remarkable  than  this  was  the  reduction 
in  the  general  death  rate  from  all  causes  of  10  per  cent, 
namely  from  22.4  to  19.9  per  thousand  living. 

Following  directly  the  success  of  the  Lawrence  filter, 
a  number  of  other  filters  were  constructed  more  or  less 
like  it,  but  none  of  them  supplying  as  large  a  city  as 
Lawrence. 

Up  to  the  year  1893  but  little  progress  had  been  made 
in  understanding  the  process  of  mechanical  filtration, 
although  many  plants  had  been  installed,  mostly  in  the 
smaller  cities  and  towns  and  in  paper  mills.  The  details 
of  construction  and  operation  had  been  developed  to  a 
considerable  extent,  but  there  was  no  adequate  knowl- 
edge of  what  could  be  done  in  securing  pure  water,  or 
how  it  could  best  be  accomplished. 

In  that  year  Mr.  Edmund  B.  Weston  made  some  tests 
for  the  city  of  Providence,  which  indicated  that  very  good 
work  could  be  done  by  mechanical  filters  in  purifying  a 
sewage-polluted  water.  These  tests  were  by  no  means 
all  that  could  be  desired,  but  they  were  important  as 
being  the  first  carefully  conducted  tests  with  that  kind 
of  filtration. 


78  WATER  PURIFICATION   IN  AMERICA. 

Meanwhile,  the  mechanical  niters  installed,  though 
often  giving  relatively  good  service,  were  not  by  any 
means  doing  so  uniformly.  The  conditions  of  success 
with  them  certainly  were  not  understood.  While  excel- 
lent results  were  occasionally  reached,  the  average  work 
was  at  best  mediocre,  and  there  were  conspicuous  cases 
of  failure  to  accomplish  the  desired  results. 

The  practical  and  scientific  basis  for  mechanical  ni- 
tration may  be  said  to  date  from  the  Louisville  experi- 
ments of  1895-97.  These  were  made  under  the  direction 
of  Mr.  Charles  Hermany,  assisted  by  Mr.  George  W. 
Fuller,  acting  for  the  Louisville  Water  Company,  and 
by  several  companies  interested  in  the  construction  of 
mechanical  filters. 

These  experiments  were  made  upon  the  Ohio  River 
water,  and  this  water  was  radically  different  in  quality 
from  the  Merrimack  River  water  which  had  been  experi- 
mented upon  at  Lawrence,  as  well  as  from  all  the  waters 
with  which  practical  experience  had  been  had  in  Europe. 

The  difference  was  principally  in  the  matters  carried 
in  suspension,  or  in  the  turbidity.  The  Ohio  River 
water  carried  varying  amounts,  and  at  times  very  large 
amounts,  of  clay  in  suspension.  Some  of  the  clay  par- 
ticles are  much  smaller  in  size  than  the  bacteria,  the 
smallest  organisms,  the  removal  of  which  has  been 
regarded  as  important.  So  finely  divided  is  some  of  this 
clay  that  it  will  hardly  settle  from  the  water  at  all. 

The  removal  of  this  clay  is  important  and  necessary 
on  its  own  account,  for  no  water  can  be  considered  ade- 
quately purified  and  satisfactory  for  a  public  water  sup- 
ply while  it  contains  any  appreciable  turbidity  of  this  kind. 


An  early  type  of  Mechanical  Filter  at  Chattanooga,  Tenn. 
Courtesy  of  American  Water  Works  and  Guarantee  Company. 


The  Little  Falls  Filters  of  the  East  Jersey  Water  Company. 
Courtesy  of  Mr.  G.  W.  Fuller. 


THE  LOUISVILLE  EXPERIMENTS.  79 

Clay  is  also  most  important  because  when  it  is  not  re- 
moved its  presence  exerts  an  influence  on  man  other 
things.  Substances  which  would  be  readily  removed  by 
a  given  treatment  in  the  absence  of  clay  particles,  may 
fail  to  respond  to  the  treatment  in  the  presence  of  such 
particles,  and  a  treatment  otherwise  successful  may  fail 
when  applied  to  a  water  containing  them. 

Now  the  Louisville  experiments  were  the  first  to  deal 
with  this  question  of  clay  particles  in  a  comprehensive 
way.  The  filtration  proposed  for  St.  Louis  by  Kirk- 
wood,  the  filtration  practiced  in  Europe,  and  the  filtration 
studied  at  Lawrence  were  hopelessly  inadequate  for  this 
business.  The  mechanical  filters  then  in  use  in  the 
United  States,  and  those  selected  and  designed  for  these 
tests  were  also  inadequate,  although  they  did  embody  to 
a  large  extent  the  ideas  that  were  to  prove  successful,  and 
were  able,  even  at  the  outset,  to  accomplish  a  great  deal. 

As  the  tests  progressed  and  the  weaknesses  of  the  vari- 
ous devices  became  apparent,  modifications  were  made, 
and  in  this  way  at  Louisville  the  first  thoroughly  success- 
ful method  of  treatment  for  this  kind  of  water  was  reached. 

The  Louisville  experiments  brought  mechanical  filtra- 
tion to  a  point  where  it  was  able  to  deal  in  an  efficient 
and  practical  manner  with  many  of  the  most  difficult  of 
American  waters. 

While  the  experiments  were  in  progress  at  Louisville, 
others  were  undertaken  by  the  city  of  Pittsburgh,  and 
Cincinnati  soon  followed.  Experiments  were  also  made 
at  Washington,  at  Superior,  and  at  New  Orleans,  and 
elsewhere.  And  as  a  result  of  these,  and  the  practical 
experiences  with  other  waters  by  the  men  having  to  dp 


8o  WATER  PURIFICATION  IN  AMERICA. 

with  them,  and  by  a  free  exchange  of  the  results  of  this 
experience  between  the  different  workers,  data  were 
rapidly  collected  as  to  the  characters  of  different  waters, 
and  as  to  the  ways  in  which  they  responded  to  different 
treatments;  and  in  this  way  a  basis  was  reached  for  lay- 
ing out  methods  of  treatment  capable  of  purifying  a  great 
range  of  waters. 

Now  the  range  in  the  qualities  of  American  waters  is 
much  greater  than  the  range  in  the  qualities  of  European 
waters.  The  excess  of  clay  which  has  already  been 
mentioned  is  a  controlling  element  in  a  considerable 
portion  of  American  river  supplies. 

With  impounding  reservoir  supplies  also  there  is  a 
difference  almost  as  important,  due  to  the  higher  sum- 
mer temperatures  and  the  growth  of  organisms,  giving 
rise  to  more  seriously  objectionable  tastes  and  odors. 
Such  growths  are  not  often  troublesome  under  European 
conditions. 

Although  the  purification  of  water  for  the  purpose  of 
removing  tastes  and  odors  is  highly  important,  it  has 
received  less  study  than  the  removal  of  clay.  Never- 
theless, something  has  been  done  with  it.  More  study 
has  been  given  to  preventive  measures  than  to  corrective 
ones,  although  there  are  strong  reasons  for  believing  at 
this  time  that  the  latter  are  more  effective. 

The  city  of  Reading,  Pa.,  made  some  experiments  in 
1897,  in  this  direction,  and  since  that  time  plants  based 
on  the  experimental  results  have  been  put  in  successful 
operation  for  cleaning  the  water  from  two  impounding 
reservoirs,  which  were  subject  to  algae  growths,  and 
objectionable  tastes  and  odors  resulting  therefrom. 


TASTES   AND    ODORS.  81 

The  Ludlow  Reservoir  at  Springfield,  Mass.,  was  one 
of  the  most  notorious  reservoirs  for  its  tastes  and  odors. 
The  city  of  Springfield  and  the  State  Board  of  Health 
made  continued  and  elaborate  experiments  upon  the 
treatment  of  this  water ,  from  1900  to  1903.  These  experi- 
ments showed  that  the  water  could  be  successfully 
treated,  though  with  rather  elaborate  appliances  and  at 
considerable  cost. 

Afterwards,  in  1906,  works  for  the  purification  of  this 
water  were  installed.  These  works  differed  somewhat 
from  anything  that  had  been  tested  during  the  previous 
experiments,  being  simpler  and  cheaper.  Only  a  par- 
tial purification  was  predicted  and  expected,  but  thus 
far  the  results  have  exceeded  expectations. 

One  of  the  most  important  of  recent  developments 
in  water  purification  has  been  the  consideration  of  a  par- 
tial softening  of  river  waters  in  connection  with  the 
other  processes  necessary  for  their  purification.  The 
idea  of  the  possibility  of  doing  this  is  very  old.  Wan- 
klyn's  "Water  Analysis,"  published  in  London  in  1868, 
spoke  at  length  of  the  possibility  of  doing  this ;  but  there 
were  practical  difficulties,  and  the  process  was  not  actu- 
ally used  at  any  place,  and  it  has  only  been  since  about 
1903  that  the  process  has  been  taken  up  in  a  way  to  re- 
move the  difficulties. 

The  development  seems  to  have  come  about  in  this 
way.  The  coagulant  most  commonly  used  in  mechan- 
ical filtration  is  sulphate  of  alumina  or  crude  alum. 
Now,  sulphate  of  iron,  or  copperas,  is  cheaper,  and 
under  some  conditions  fully  as  efficient  as  sulphate  of 
alumina  as  a  coagulant.  With  the  iron  it  is  necessary 


82  WATER  PURIFICATION  IN  AMERICA. 

to  use  lime,  as  without  it  precipitation  is  not  sufficiently 
rapid  and  complete.  Only  a  little  lime,  comparatively, 
is  needed  to  throw  down  the  iron.  A  considerably 
larger  quantity  will  also  throw  down  some  of  the  lime 
naturally  present  in  the  water,  together  with  the  lime 
that  is  added.  This  is  the  old  and  well  known  Clark 
process  for  softening  water,  which  is  the  basis  of  all 
water-softening  methods. 

In  1903,  the  iron  and  lime  process  of  treating  water 
was  applied  to  the  Mississippi  River  water  supplied  to 
St.  Louis.  In  this  case  the  water,  after  the  chemical 
treatment,  passed  through  settling  basins  but  was  not 
filtered.  At  Quincy,  111.,  Lorain,  Ohio,  and  other  places 
it  was  applied  as  a  preliminary  to  nitration.  And  it  was 
soon  found  that  when  the  amount  of  lime  was  increased, 
accidentally  or  otherwise,  the  resulting  effluent  was 
often  softer  than  the  river  water.  And  when  this  was 
found  it  naturally  led  to  the  regular  use  of  more  lime  and 
perhaps  of  less  iron.  In  this  way  a  substantial  amount 
of  softening  was  effected,  at  St.  Louis  and  elsewhere,  by 
the  iron  and  lime  process. 

The  matter  was  investigated  by  an  exhaustive  series 
of  experiments  at  Columbus,  Ohio,  and  the  process  was 
developed  with  a  view  to  a  combined  coagulation  and 
softening  treatment  prior  to  nitration.  Works  have  since 
been  built  upon  this  principle  and  successfully  operated 
at  Columbus  and  at  several  other  cities. 

The  use  of  partial  softening  brought  about  in  this  way 
does  not  greatly  increase  the  cost  over  that  of  the  treat- 
ments otherwise  necessary  for  purification.  It  is  even 
possible  that  with  some  river  waters  the  process  may  be 


Coagulating  Devices  at  Watertown,  N.  Y. 


Covered  coagulating  basins  and  mechanical  filters  in  course  of  con- 
struction at  Watertown,  N.  Y. 


METHODS  OF  COAGULATION.  83 

actually  cheapened.  If  this  result  is  secured  it  will  be 
by  making  use  of  the  magnesia  of  the  water  to  do  a  part 
of  the  work  otherwise  accomplished  by  alumina  or  iron. 
This  will  not  always  be  possible,  but  even  when  it  is  not, 
the  advantage  of  soft  water  to  a  city  is  so  great  that  large 
expenditures  can  well  be  made  to  secure  it  where  the 
natural  supply  is  hard. 

While  these  advances  have  been  made  in  the  knowl- 
edge of  the  processes  of  purification,  and  of  the  means  of 
carrying  them  out  with  success,  an  almost  equal  advance 
has  been  made  in  the  materials  of  construction  of 
mechanical  filters  and  in  their  detailed  arrangements. 

The  Hyatt  patent,  the  underlying  patent  on  mechan- 
ical filters,  expired  in  February,  1901.  After  that  the 
field  was  open.  All  other  patents  related  to  details;  and 
no  one  of  them,  nor  even  any  combination  of  them, 
could  serve  to  control  the  field  of  filter  construction. 

From  that  day  rapid  advances  were  made.  The  de- 
signs for  the  Louisville  filters,  which  appeared  in  1900, 
were  important  as  marking  the  beginning  of  a  rapid  ad- 
vance. Reinforced  concrete  was  substituted  for  the  wood 
and  iron  constructions  previously  used.  The  Little  Falls 
filters,  treating  the  supply  of  the  East  Jersey  Water  Com- 
pany, were  put  in  service  in  September,  1902,  and  were 
the  first  filters  to  be  actually  used  on  the  newer  lines. 
These  filters  were  also  equipped  with  appliances  for  the 
better  and  more  certain  control  of  coagulants  and  were 
far  better  in  other  ways  than  any  before  constructed. 

The  use  of  larger  coagulating  basins  to  allow  the 
chemical  changes  to  become  complete  before  the  water 
passed  to  the  filters  was  early  introduced  at  a  number  of 


84  WATER  PURIFICATION  IN  AMERICA. 

Missouri  River  points,  especially  at  the  works  owned  by 
the  American  Water  Works  and  Guarantee  Company,  at 
East  St.  Louis,  III,  and  at  St.  Joseph,  Mo. 

The  use  of  cement  blocks  for  the  bottoms  of  the  niters, 
containing  the  necessary  channels  for  the  effluent  and 
wash  water,  in  place  of  the  metal  structures  previously 
used,  was  introduced  at  the  niters  of  the  Hackensack 
Water  Company,  built  in  1904,  and  is  also  used  with 
modifications  at  Columbus,  New  Orleans,  and  elsewhere. 

While  these  rapid  and  revolutionary  developments  in 
mechanical  filters  have  been  taking  place,  sand  filters, 
following  European  precedent,  have  been  installed  in 
many  places  where  the  conditions  have  been  suitable  and 
in  a  few  places  where  they  were  not,  and  developments 
with  them  also  have  taken  place. 

Following  the  Lawrence  filter,  the  first  large  installa- 
tion was  at  Albany,  put  in  service  in  1899.  These  filters 
were  covered  by  masonry  vaulting  as  a  protection  from 
frost,  which  had  interfered  more  or  less  with  the  winter 
operation  at  Poughkeepsie  and  at  Lawrence.  Such  cov- 
ers had  long  been  used  in  Germany  for  the  same  purpose, 
and  also  at  a  few  small  American  plants. 

The  Albany  filters  received  water  from  the  Hudson 
River  a  few  miles  below  the  outlets  of  the  Troy  sewers. 
The  death  rate  in  Albany  was  reduced  by  the  use  of  the 
filters  as  much  as  it  has  been  at  Lawrence. 

At  Philadelphia  the  construction  of  covered  sand  filters 
was  started  in  1900,  but  the  work  went  forward  slowly 
and  it  was  November,  1911,  before  the  whole  supply  was 
filtered. 

At  Washington  the  construction  of  covered  sand  niters 


SAND  FILTERS.  85 

was  authorized  in  1902,  and  the  plant  was  put  in  service 
in  1905.  In  this  case  there  has  been  no  marked  reduc- 
tion in  the  death  rate.  The  reason  for  this  has  been 
made  clear  by  extended  investigations.  The  Potomac 
River  water  used  for  supplying  the  city,  after  passing 
through  the  settling  basins,  which  held  a  week's  supply, 
and  in  which  much  bacterial  purification  took  place,  was 
not  the  principal  source  of  typhoid  fever  in  Washington 
nor  an  important  cause  of  other  water-borne  diseases. 

The  amount  of  sewage  entering  the  Potomac  above 
the  intake  is  only  a  small  fraction  of  the  amounts  entering 
the  Merrimack  above  Lawrence  and  the  Hudson  above 
Albany. 

Providence  installed  a  sand  filtration  plant,  which  was 
put  in  service  in  1905.  Denver  is  malyily  supplied  by 
water  from  sand  filters,  in  service  since  1902.  Pittsburgh 
has  built  an  extensive  plant  with  covered  filters  which 
has  been  in  service  since  1909. 

Among  the  improvements  in  sand  filters  are  the  devel- 
opments of  methods  of  washing  and  preparing  filter 
sand,  and  of  cheaply  removing  and  cleaning  it  after  it 
has  become  dirty  from  use,  and  of  replacing  it. 

The  first  of  these  improvements  has  made  it  possible 
to  secure  at  moderate  expense  a  filter  sand  of  the  best 
quality  in  places  where  otherwise  the  use  of  filters  of 
this  type  would  have  been  difficult.  The  second  has 
resulted  in  a  great  reduction  in  the  cost  of  filtration.  For 
example,  the  cost  of  labor  for  removing,  washing,  and 
replacing  sand  at  Washington  is  about  $0.60  per  million 
gallons,  as  compared  with  about  $6.00  at  Lawrence  in 
the  early  days  before  labor-saving  devices  were  installed. 


86 


WATER  PURIFICATION  IN  AMERICA. 


PARTIAL  LIST  OF  PLACES  IN  THE  UNITED  STATES  WHERE  FIL- 
TERS ARE  AT  PRESENT  IN  USE 

MECHANICAL  FILTERS 


Place. 


Population, 
1910. 


Capacity  of 
filters  in  mil- 
lions of  gallons 
per  day. 


Cincinnati 363,591 

New  Orleans 339,075 

Minneapolis 301,408 

East  Jersey  Water  Co 300,000 

Hackensack  Water  Co 250,000 

Louisville 223,928 

Columbus 181,548 

Toledo 168,497 

Atlanta 154,839 

Scranton 129,867 

Grand  Rapids .  ^.* 112,571 

Kansas  City,  Kan. 82,331 

Youngstown 79,066 

St.  Joseph 77,403 

Fort  Worth 73,312 

Evansville 69,647 

Norfolk 67,452 

Oklahoma  City,  Okla 64,205 

Harrisburg 64,186 

Charleston 58,833 

East  St.  Louis 58,547 

Terre  Haute 58,157 

Binghamton 48,443 

Little  Rock 45,94* 

York 44,750 

Chattanooga 44,604 

Davenport 43,°28 

McKeesport 42,694 

Augusta,  Ga 41,040 

Macon 40,665 


112 

44 

20 

32 
24 

37 
30 
20 

21 

6 

20 

6 

ii 

ii 

5 

12 

8 
4 

12 

5 

ii 

9 
8 

5 
4 

9 
7 

10 
6 


FILTERS  IN  USE. 
MECHANICAL  FILTERS — Continued. 


Place. 


Population] 
1910. 


Capacity  of 
filters  in  mil- 
lion of  gallons 
per  day. 


San  Diego 39,578 

Chester 38,537 

Montgomery 38,136 

Elmira 37,J76 

Quincy 36,587 

Knoxville 36,346 

Newcastle 36,280 

Springfield,  Mo 35,2Qi 

Lexington,  Ky 35,°99 

Oshkosh,  Wis 33,062 

Cedar  Rapids 32,81 1 

Decatur 31,140 

Niagara  Falls 30,445 

Lorain 28,883 

Danville,  111 27,871 

Newport,  R.  1 27,149 

Watertown,  N.  Y 26,730 

Waterloo,  la 26,693 

Columbia,  S.  C 26,319 

Elgin 25,976 

Kingston 25,908 

Wilmington,  N.  C 25,748 

Newark,  Ohio 25,404 


16 

9 
6 

6 
6 

's 

2 


And  about  250  smaller  plants. 


88  WATER  PURIFICATION  IN  AMERICA. 

SAND  FILTERS. 


Place. 

Population, 
1910. 

Capacity  of 
filters,  million 
gallons  per 
day. 

Philadelphia  

I  ,  tJAQ  008 

4.2O 

Pittsburgh 

C77  one 

IOO 

Toronto                

376  <u8 

60 

Washington  

•2-21,060 

87 

Indianapolis 

277  6^O 

2A 

Providence  

224.,  326 

24. 

Denver 

217    78l 

3O 

New  Haven  

177  6O<\ 

I  c 

Albany  

IOO,2^3 

17 

Reading 

06  O7I 

22 

Springfield  

88,026 

ie 

Wilmington 

8?  4.II 

I  e 

Lawrence  

8^,802 

6 

Yonkers  

70,803 

IO 

Superior   .    . 

4.0  ^84. 

5" 

Mount  Vernon  

30,010 

7 

Poughkeepsie 

27  0^6 

5" 

And  about  25  smaller  places. 


CHAPTER  IX. 

ON  THE  NATURE  OF  THE  METHODS  OF 
PURIFYING  WATER. 

THE  general  natures  of  these  methods  are  elsewhere 
noted  in  connection  with  the  descriptions  of  different 
kinds  of  water  that  require  treatment.  A  brief  state- 
ment of  the  natures  of  the  various  processes  at  this  point 
may  be  helpful,  even  though  some  of  the  matter  is 
repeated. 

The  processes  of  water  purification  may  be  briefly 
classified  as  follows: 

I.   Mechanical  Separation: 

By  gravity  —  Sedimentation. 

By  screening  —  Screens,  scrubbers,  filters. 

By  adhesion  —  Scrubbers,  niters. 

II.    Coagulation: 

By  chemical  treatment  resulting  in  drawing  matters 
together  into  groups,  thereby  making  them  more 
susceptible  to  removal  by  mechanical  separation,  but 
without  any  significant  chemical  change  in  the  water. 

III.  Chemical  Purification: 

Softening  —  by  the  use  of  lime,  etc. 

Iron  removal. 

Neutralization  of  objectionable  acids,  etc 

IV.  Disinfecting  Processes: 

[Hypo chlorite  of  lime. 
Chlorine  gas. 
Ozone. 

Sulphate  of  copper. 
Violet  ray  treatment. 

89 


90  METHODS  OF  PURIFYING  WATER. 

The  object  of  these  processes  is  to  poison  and  kill  objec< 
tionable  organisms,  without  at  the  same  time  adding 
substances  objectionable  or  poisonous  to  the  users 
of  the  water. 

V.  Biological  processes: 

Oxidation  of  organic  matter  by  its  use  as  food  for  organ- 
isms which  thereby  effect  its  destruction. 

Death  of  objectionable  organisms,  resulting  from  the 
production  of  unfavorable  conditions,  such  as  absence 
of  food  (removed  by  the  purification  processes)  kill- 
ing by  antagonistic  organisms,  etc. 

VI.  Aeration: 

Evaporation  of  gases  held  in  solution  and  which  are  the 
cause  of  objectionable  tastes  and  odors. 

Evaporation  of  carbonic  acid,  a  food  supply  for  some 
kinds  of  growths. 

Supplying  oxygen  necessary  for  certain  chemical  purifi- 
cations, and  especially  necessary  to  support  growths 
of  water-purifying  organisms. 
VH.  Boiling: 

The  best  household  method  of  protection  from  disease- 
carrying  waters. 

These  are  the  most  important  ways  in  which  water  is 
cleaned  and  purified,  but  the  classification  is  necessarily 
imperfect  and  inadequate  because  each  of  the  actions 
mentioned  is  related  to  and  grades  into  some  of  the 
others,  and  in  many  cases  it  cannot  be  determined  how 
much  of  the  purification  effected  by  a  given  process  is 
brought  about  in  one  way  and  how  much  in  another. 
For  instance,  in  filtration  it  is  known  that  the  straining 
out  of  suspended  matters,  the  sedimentation  taking  place 
in  the  pores  of  the  filtering  material,  and  the  adhesion 
of  the  suspended  particles  to  fixed  particles  of  filter- 


PROCESSES  OF  PURIFICATION.  QI 

ing  material,  are  all  important  in  bringing  about  purifi- 
cation, and  in  addition,  there  is  also  taking  place  at  the 
same  time  and  in  the  same  place  a  whole  series  of  biologi- 
cal changes,  so  complicated  that  at  the  present  time  only 
a  general  outline  of  their  nature  is  understood. 

In  a  similar  way,  coagulation  is  usually  effected  by  a 
chemical  process,  and  some  chemical  change  in  the 
water  is  produced  by  the  treatment,  although  this  is  not 
its  direct  and  principal  object. 

Sometimes  two  processes  are  combined,  as  where  river 
water  is  softened  by  chemical  treatment  in  such  a  way 
as  to  produce  a  coagulating  effect  upon  the  suspended 
matters. 

Many  of  the  disinfectants  are  powerful  oxidizing 
agents.  Hypochlorate  of  lime,  liquid  chlorine,  and 
ozone  are  among  the  most  powerful  oxidizing  agents 
known.  In  addition  to  killing  the  objectionable  organ- 
isms, there  is  sure  to  be  direct  chemical  action  resulting 
from  these  substances  which  tends  to  the  purification  of 
the  water,  and  at  the  same  time  to  the  destruction  and 
elimination  of  the  applied  substances  from  the  water. 
These  secondary  actions  are  often  of  great  importance. 
If  ozone  is  applied  to  a  dirty  water  in  quantity  sufficient 
to  kill  the  objectionable  organisms  in  clean  water,  it  may 
happen  that  the  impurities  in  the  water  will  absorb  and 
use  up  the  ozone  so  rapidly  that  it  will  not  have  a  chance 
to  act  upon  the  organisms,  and  the  desired  effect  will  not 
be  produced.  For  this  and  other  reasons  it  is  not  advis- 
able to  apply  such  oxidizing  agents  to  dirty  raw  water. 
So  far  as  they  can  be  used  with  advantage  they  must 
be  applied  to  waters  that  have  already  been  filtered  and 


92  METHODS  OF  PURIFYING  WATER. 

oxidized  and  largely  purified  by  other  and  cheaper 
methods. 

Straining.  This  is  used  particularly  to  remove  fish 
and  floating  leaves,  sticks,  etc.  Coarse  screening  is  best 
effected  by  passing  between  steel  bars  arranged  to  be 
easily  raked  off.  Fine  screening  is  most  frequently  done 
through  screens  covered  with  wire  cloth,  arranged  in 
pairs  so  that  one  screen  is  raised  for  cleaning  while  its 
mate  is  below  in  service.  Such  screens  are  often  made 
large  and  heavy  and  are  raised  by  hydraulic  or  electric 
power. 

Revolving  screens  are  also  used,  and  they  are  better. 
They  are  of  two  general  types.  In  one  the  screen  runs 
as  a  link-belt  over  pulleys  above  and  below;  in  the  other 
the  screen  is  in  the  form  of  a  cylinder  partly  immersed  in 
the  water  and  passing  between  guides  which  insure  the 
passage  of  all  the  water  through  it.  In  either  case  the 
motion  of  the  screens  is  continuous,  and  cleaning  is  done 
in  the  part  of  the  screen  above  the  water  by  jets  of  water 
playing  upon  it. 

Screens  are  largely  used  in  paper  mills,  wire  cloth 
having  as  many  as  sixty  meshes  per  lineal  inch  being 
often  employed. 

Many  elaborate  screening  arrangements  have  been 
installed  for  unfiltered  reservoir  waters,  in  the  hope  that 
algae  and  other  organisms  would  be  removed  by  them. 
Some  organisms  are  removed,  but  the  most  troublesome 
ones  and  their  effects  are  not  removed  or  even  sensibly 
reduced  by  screening. 

Screening  as  a  preliminary  to  filtration  is  often  used, 
and  within  certain  limits  is  advantageous;  but  close 


SEDIMENTATION.    SCRUBBERS.  OJ 

screening  is  unnecessary,  and  in  many  plants  there  is  no 
screening  before  nitration  and  no  need  of  it. 

Sedimentation.  This  consists  in  taking  water  through 
tanks  or  basins  in  which  the  velocity  of  flow  is  reduced 
and  the  heavier  suspended  matters  are  taken  to  the  bot- 
tom by  gravity.  The  accumulated  sediment  is  removed 
from  time  to  time.  Sedimentation  is  widely  used  as  a 
preliminary  process  and  is  the  cheapest  way  of  removing 
those  relatively  large  particles  which  will  settle  out  in  a 
moderately  short  length  of  time. 

It  pays  to  remove  such  particles  in  this  way  when  they 
are  numerous,  even  though  other  and  more  thorough 
processes  are  to  follow,  as  the  subsequent  processes  are 
more  easily  and  effectively  carried  out  in  the  absence  of 
heavy  suspended  matters. 

Scrubbers.  These  are  rapid,  coarse-grained  niters,  or 
their  equivalent.  They  have  been  used  to  a  consider- 
able extent  in  recent  works.  To  some  extent  they  are 
used  in  place  of  sedimentation,  doing  about  the  same 
work,  but  doing  it  quicker  and  in  less  space,  though  usu- 
ally at  greater  cost;  and  to  some  extent  they  carry  the 
process  further,  removing  smaller  and  lighter  particles 
than  could  be  readily  removed  by  settling  alone. 

Scrubbers  act  in  part  as  strainers,  but  the  principal 
action  is  apparently  the  sedimentation  which  takes  place 
in  the  pores  of  the  scrubbing  material,  where  conditions 
of  sedimentation  are  extremely  favorable. 

It  is  very  easy  to  build  a  scrubber  to  do  good  work.  It 
is  more  difficult  to  build  one  to  do  this  and  also  be 
capable  of  being  cleaned  in  a  cheap  and  efficient  man- 
ner. From  the  standpoint  of  design  and  construction, 


94  METHODS   OF  PURIFYING   WATER. 

the  cleaning  devices  are  the  most  important  parts  of  a 
scrubber. 

Mechanical  Filters.  This  is  a  most  important  type  of 
apparatus.  It  is  an  arrangement  for  passing  water 
through  a  sand  layer  at  a  relatively  high  rate,  with  devices 
for  cleaning  the  sand  when  it  becomes  dirty,  by  revers- 
ing the  current,  and  by  other  means,  and  of  all  necessary 
auxiliary  apparatus  for  regulating  and  controlling  the 
process. 

The  term  mechanical  filter  came  from  the  mechanical 
nature  of  the  appliances  used  for  cleaning  the  sand. 

There  are  many  types  of  mechanical  filters  and  there 
has  been  a  great  development  in  the  devices  used.  The 
substitution  of  concrete,  bronze,  and  other  durable 
materials  for  the  wood  and  the  rapidly  corroded  iron 
and  brass  of  the  earlier  designs,  is  conspicuous,  but  in 
addition,  developments  in  the  direction  of  simpler  and 
more  adequate  and  effective  devices  have  been  most 
important. 

From  the  standpoint  of  design  and  construction  the 
cleaning  devices  offer  far  greater  difficulties  than  the 
filtering  devices. 

In  mechanical  filters  the  straining  action  is  probably 
more  important  than  the  sedimentation  taking  place  in 
the  pores  of  the  filtering  material. 

In  a  few  cases  mechanical  filters  have  been  used  as  a 
first  or  preliminary  process,  but  usually  they  are  em- 
ployed as  a  final  process  of  purification.  To  make  them 
effective  in  this  way  the  water  reaching  them  must  be 
thoroughly  prepared  by  coagulation  or  otherwise.  That 
is  to  say,  all  extremely  small  particles  must  have  been 


Interior  of  Filter  House.  Little  Falls  Filters  of  the  East  Jersey 
Water  Company,  showing  operating  table  for  mechanical 
filters. 

Courtesy  of  Mr.  G.  W.  Fuller. 


Bottom  of  a  mechanical  filter  at  Watertown,  N.  Y.,  with  the  sand 
removed  to  show  the  water  and  air  piping  and  strainers. 


SAND   FILTERS.  95 

drawn  together  into  aggregates  of  sufficient  size  to  be 
capable  of  being  removed  by  nitration  at  a  high  rate,  and 
the  total  amount  of  such  particles  must  have  been  re- 
duced by  subsequent  sedimentation  to  such  a  quantity 
that  the  filtering  material  will  not  be  too  rapidly  clogged 
by  them.  Without  such  thorough  preliminary  treat- 
ment mechanical  filters  are  not  capable  of  removing  the 
bacteria,  or  the  finely  divided  sediment  or  turbidity,  and 
many  other  matters  requiring  to  be  removed. 

Sand  Filters.  Sand  filters  are  used  at  a  lower  rate  than 
mechanical  filters,  and  cleaning  is  done  by  removing  by 
scraping  of  a  surface  layer  of  dirty  sand  instead  of  by 
washing  the  whole  sand  layer  by  a  reverse  current.  The 
cost  of  cleaning  devices  being  saved,  and  construction 
simplified  in  other  ways,  as  compared  with  mechanical 
filters,  a  far  greater  filtering  area  can  be  provided  for  the 
same  cost;  and  filtration  being  at  a  lower  rate,  the  strain- 
ing action  is  more  thorough,  and  there  are  opportunities 
for  biological  purification.  Sand  filtration  alone,  without 
preliminary  treatment,  is  able  to  remove  nearly  all  of  the 
objectionable  bacteria,  as  well  as  other  organisms,  from 
many  waters,  at  the  same  time  purifying  them  in  other 
ways.  The  straining  is  not  close  enough,  however, 
to  remove  the  clay  particles  that  render  many  waters, 
especially  some  river  waters,  turbid,  and  such  waters 
require  preliminary  treatment. 

Sand  filters  are  used  in  connection  with  various  pre- 
liminary treatments,  but,  generally  speaking,  they  are 
adapted  to  treating  only  such  waters  as  are  capable  of 
being  purified  in  that  way  without  any  preliminary  treat- 
ments, or  with  only  rough  and  inexpensive  treatments, 


96  METHODS   OF   PURIFYING   WATER. 

If  the  water  ordinarily  requires  coagulation,  then,  as  a 
rule,  it  will  be  better  to  make  the  coagulation  thorough 
and  use  mechanical  niters  for  the  final  treatment. 

Coagulating  Devices.  Coagulating  devices  consist  of 
apparatus  for  dissolving  the  chemical  or  chemicals  used 
for  coagulating  the  water,  and  for  mixing  the  solutions, 
and  bringing  them  to  the  required  strengths,  and  for  ap- 
plying them  to  the  water,  and  mixing  them  with  it,  and 
all  auxiliary  appliances. 

There  is  great  variety  in  coagulating  devices,  and  much 
ingenuity  has  been  displayed  in  meeting  special  condi- 
tions. There  is  no  great  or  insuperable  difficulty  in  se- 
curing the  regular  and  proper  addition  of  coagulant  to  a 
water,  and  in  many  cases  this  has  been  done  in  a  perfectly 
satisfactory  way.  On  the  other  hand,  the  coagulating 
devices  have  probably  failed  to  act  more  frequently  than 
any  other  part  of  the  plants  of  which  they  form  parts, 
and  for  this  reason  the  greatest  care  must  be  given  to 
their  design  and  operation. 

In  the  last  few  years  a  new  type  of  coagulating  apparatus 
has  appeared,  known  as  the  dry-feed  apparatus.  With  it 
the  chemical  in  pulverized  form  is  fed  mechanically  at  a 
fixed  rate  to  a  dissolving  box.  An  excess  of  water  flows 
through  this  and  dissolves  the  chemical  as  it  is  delivered 
and  afterwards  mixes  with  the  water  to  be  treated.  The 
rate  of  application  is  controlled  by  changing  the  gearing 
or  other  mechanical  control. 

The  dry-feed  process  originated  in  St.  Louis,  but  in  this 
case  the  chemicals  were  weighed  out  and  put  by  hand  into 
the  dissolving  box  at  determined  intervals.  The  same 


Coagulating  and  sedimentation  basin  with  aeration  of  entering 
water  and  with  thorough  baffling  to  assist  sedimentation. 
South  Pittsburgh  filters. 


Coagulating   and   sedimentation   basin  with  baffles    and    pumping 

station  and  filter  house  at  St.  Joseph,  Missouri. 
Courtesy  ov  American  Water  Works  and  Guarantee  Company. 


COAGULATING  BASINS.  97 

general  method  has  been  followed  at  Cincinnati  and  more 
recently  at  Washington. 

The  more  recently  installed  machines  have  been  made 
entirely  automatic  in  their  action,  and  after  filling  the 
attached  hoppers,  which  may  hold  hours'  or  even  days7 
supply,  the  application  is  continued  without  labor  and 
with  only  occasional  attention  at  the  rate  for  which  they 
are  set. 

Coagulating  Basins.  Coagulating  basins  are  required  to 
hold  the  water  for  a  time  after  it  has  received  the  coagulant 
or  coagulants,  to  allow  the  chemical  reactions  resulting 
from  the  treatment  to  take  place.  They  also  serve  to  re- 
move by  sedimentation  the  greater  part  of  the  precipitate 
that  results  from  these  reactions.  This  feature  is  of  the  ut- 
most importance,  as  otherwise  the  precipitate  would  choke 
the  filters,  and  cleaning  would  be  required  too  frequently. 
The  bulk  of  the  precipitates  should  always  be  removed 
before  the  water  goes  to  the  filter,  and  to  this  end  baffles 
and  other  devices  tending  to  complete  sedimentation  are 
desirable,  and  the  bottoms  of  the  basins  are  made  with 
slopes  and  gutters  to  facilitate  the  easy  and  frequent 
removal  of  the  mud  which  is  deposited  upon  them. 

Aerating  Devices.  Aerating  devices  are  used  to  bring 
the  water  in  contact  with  air,  either  for  the  purpose  of 
introducing  oxygen  or  of  removing  carbonic-  acid  or 
gases  which  produce  tastes  and  odors.  The  natural 
flow  of  water  in  the  bed  of  a  mountain  stream  having  a 
rapid  fall  aerates  it  in  a  most  effective  way,  and  many 
works  are  so  arranged  that  this  kind  of  aeration  is  uti- 
lized. Flow  in  sluggish  streams  or  canals  has  compara- 
tively little  value  for  aeration. 


98  METHODS  OF  PURIFYING  WATER. 

When  aeration  must  be  done  with  artificial  appliances, 
playing  the  water  in  jets  forming  fountains  is  one  of  the 
most  effective  ways,  but  to  be  thoroughly  efficient  con- 
siderable head  is  used  up,  and  this  is  a  serious  obstacle, 
when  the  water  is  pumped,  because  of  the  cost.  In  other 
cases  the  water  is  allowed  to  fall  through  the  perforated 
bottoms  of  trays,  and  similar  devices.  Under  some 
conditions  flowing  over  or  through  coke  or  other  coarse- 
grained ballast  seems  to  aid,  but  it  is  essential  that  the 
air  in  the  voids  of  such  material  should  be  frequently 
changed  by  some  certain  means,  as  otherwise  the  materials 
instead  of  being  helpful  will  greatly  reduce  the  amount 
of  aeration  obtained. 

When  aeration  is  used  to  introduce  oxygen,  a  sub- 
stantial result  may  be  obtained  by  well  designed  appli- 
ances with  a  drop  of  not  more  than  two  or  three  feet  in 
water  level.  Much  more  extended  aeration  is  required 
to  remove  objectionable  gases  from  a  water,  and  a 
greater  head  may  be  advantageously  used  where  they 
are  troublesome. 

Intermittent  niters  can  be  operated  so  as  to  thoroughly 
aerate  the  water  passing  them,  so  long  as  the  water  quan- 
tity and  the  amount  of  organic  matter  in  it  are  not  too 
large,  having  reference  to  the  grain-size,  depth,  and 
condition  of  the  filter  sand;  and  for  this  reason  this  form 
of  filtration  has  advantages  when  much  aeration  is 
required. 

The  above  outlines  of  the  most  important  processes 
of  water  purification,  and  of  the  appliances  used  to  carry 
them  out,  is  intended  only  to  give  a  general  idea  of  what 
is  aimed  at,  and  of  the  objects  of  the  various  parts  of  the 


Aeration  of  Hemlock  Lake  water  at  Rochester,  N.  Y.,  resulting 

in  a  reduction  of  tastes  and  odors. 

Courtesy  of  Mr.  Emil  Kuichling. 


An  Efficient  Aerator.    Temporary  Bronx  Supply,  New  York  City. 


AERATING  DEVICES.  99 

works,  and  no  detailed  descriptions  are  necessary  for 
this  purpose.  In  the  same  way  only  those  methods  and 
appliances  of  some  practical  importance  are  included. 
A  great  number  of  other  processes  have  been  proposed, 
and  a  few  of  them  may  be  in  time  developed  so  as  to  be 
of  practical  value.  But  a  discussion  of  such  processes, 
not  yet  brought  to  successful  application,  would  not  aid 
in  a  clear  understanding  of  first  principles. 

It  is  worth  noting  that  most  of  the  advance  in  water 
purification  comes  from  the  development  of  old  processes. 
It  is  only  at  long  intervals  that  a  new  method  or  principle 
of  treatment  is  discovered  that  is  important  enough  to 
find  a  permanent  place  in  the  art. 


CHAPTER  X. 
DISINFECTION. 

THE  possibility  of  protecting  the  users  of  water  from 
infection  carried  by  it  by  means  of  chemical  treatment 
has  been  recognized  almost  since  the  discovery  of  the 
part  played  by  water  in  transmitting  certain  disease 
germs. 

At  about  the  time  of  the  cholera  epidemic  in  Hamburg 
the  German  technical  papers  contained  discussions  of 
the  availability  of  a  number  of  metallic  salts  for  use  in 
this  way;  and  in  the  years  that  followed  some  of  these, 
especially  copper  sulphate  and  permanganate  of  potash, 
were  occasionally  used,  most  often  in  small  or  special 
supplies.  For  instance,  permanganate  of  potash,  was 
used  in  treating  waters  supplied  to  armies  in  certain 
campaigns,  and  the  benefits  from  its  use  were  undoubtedly 
great. 

Treating  water  in  this  way  may  be  compared  to  spray- 
ing fruit  trees.  Its  object  is  to  prevent  the  propagation  of 
organisms  that  would  be  destructive,  and  to  do  this  by 
the  use  of  substances  that  are  not  injurious  to  those 
that  are  to  be  protected. 

Little  progress  was  made  in  applying  processes  of 
disinfection  to  public-water  supplies  until  the  year  1908. 
Chemical  treatment  was  involved  in  them,  and  popular 
prejudice  against  its  use  was  strong.  In  that  year,  to 


DISINFECTION  OF  WATER.  %          IOI 

meet  an  urgent  need  for  greater  bacterial  efficiency, 
one  of  the  best  and  least  injurious  disinfectants,  hypo- 
chlorite  of  lime,  was  added  to  water  drawn  from  the 
Boonton  reservoir  to  supply  Jersey  City.  It  was  found 
that  in  this  way  a  great  reduction  in  bacteria  was 
obtained,  and  this  result  was  reached  with  a  smaller 
amount  of  the  disinfectant  than  could  have  been  antic- 
ipated from  any  previous  experience  on  a  small  scale. 
The  fact  of  the  great  efficiency  of  very  small  doses  of 
this  substance  has  been  amply  demonstrated  by  subse- 
quent experience,  although  the  reason  for  its  efficiency 
has  never  been  fully  explained. 

Prior  to  the  date  mentioned  efforts  had  been  made  for 
many  years  to  use  ozone  as  a  disinfectant.  Ozone  is 
produced  by  the  discharge  of  high-tension  electricity 
through  air  under  certain  conditions.  The  air  is  after- 
wards pumped  through  the  water  to  be  treated,  or  other- 
wise the  water  is  showered  downward  through  towers 
in  which  the  air  that  has  been  ozonized  is  circulated. 

In  the  early  ozonizers  a  large  amount  of  current  was 
required  to  produce  a  small  amount  of  ozone  and  the 
process  was  an  expensive  one.  It  is  necessary  for  success 
to  bring  the  ozonized  air  into  intimate  contact  with  all 
of  the  water  to  be  treated  and  the  difficulty  of  doing  this 
proved  to  be  great  and  added  to  the  expense  of  apply- 
ing it. 

The  efficiency  of  the  ozone  treatment  properly  and 
adequately  carried  out  had  been  abundantly  demon- 
strated, although  the  difficulties  and  expense  had  pre- 
vented its  practical  application  on  a  large  scale. 

It  was  soon  discovered  that  the  hypochlorite  of  lime  was 


102  DISINFECTION. 

practically  equivalent  in  disinfecting  power  to  ozone, 
on  the  basis  of  molecule  for  molecule  of  effective  oxidizing 
material.  The  hypochlorite  of  lime  produced  practically 
equivalent  results  from  the  standpoint  of  disinfection, 
at  a  cost  so  low  that  it  could  be  used  in  any  public  water- 
works plant  where  it  was  required  or  advantageous. 
The  cost  of  the  material  was  frequently  not  more  than 
fifteen  to  twenty-five  cents  per  million  gallons;  and  even 
when  the  greater  cost  of  applying  it  was  taken  into  account, 
the  whole  cost  of  the  treatment,  including  capital  charges, 
might  not  be  more  than  a  tenth  of  the  cost  of  filtration. 

When  the  advantages  to  be  obtained  by  this  simple 
and  inexpensive  treatment  became  realized,  as  a  result 
of  the  publicity  given  by  the  Jersey  City  experience, 
the  use  of  the  process  extended  with  unprecedented 
rapidity,  until  at  the  present  time  the  greater  part  of  the 
water  supplied  in  cities  in  the  United  States  is  treated 
in  this  way  or  by  some  substitute  and  equivalent  method. 

Method  of  Treatment.  Hypochlorite  of  lime,  or 
bleaching  powder,  is  a  by-product  from  the  manufacture 
of  soda  ash,  and  is  readily  obtainable  in  large  quantities. 
The  material  is  dissolved  in  water  in  large  tanks,  and 
thoroughly'mixed,  making  a  solution  of  standard  strength. 
This  solution  is  applied  through  control  devices  to  the 
water  to  be  treated. 

It  is  necessary,  in  order  to  secure  the  full  efficiency, 
that  the  solution  should  be  thoroughly  and  quickly 
mixed  with  the  water  to  be  treated,  and  it  is  desirable 
that  the  water  after  receiving  the  dose  should  be  kept 
from  mixing  with  the  other  water  that  has  been  previ- 
ously treated,  as  would  be  the  case  if  it  were  to  be 


Coagulant  House,  Washington   Filters,  where  chemicals  are  mixed 
and  applied  to  the  water  before  filtration. 


Measuring-tanks  for  Controlling  the  Application  of  Hypochlorite 
of  Lime  to  Filter  Effluents,  Yonkers,  N.  Y. 


METHOD  OF  TREATMENT.       .  103 

discharged  at  once  after  treatment  into  a  large  reservoir. 
It  suffices  if  the  treated  water  flows  for  some  distance 
in  a  pipe  or  aqueduct,  or  is  kept  in  a  small  chamber  or  a 
compartment  in  a  large  one. 

This  treatment  has  been  carried  out  as  an  independent 
process  for  many  waters  that  are  not  otherwise  purified. 
It  has  also  come  to  be  a  well-established  auxiliary  process 
to  filtration.  Considerable  chemical  skill  is  required 
to  secure  the  utmost  results  to  be  obtained  in  any  case 
without  on  the  other  hand  producing  certain  undesirable 
conditions  which  result  from  an  overdose. 

All  natural  waters  contain  more  or  less  organic  matter 
capable  of  absorbing  chlorine,  which  is  the  active  prin- 
ciple of  the  hypochlorite  of  lime.  The  absorption  of 
chlorine  goes  on  gradually  and  is  ordinarily  complete. 
That  is  to  say,  before  the  water  reaches  the  consumer, 
the  organic  matters  in  the  water  take  up  all  the  chlorine 
that  is  applied.  The  dose  must  be  adjusted  to  the  water 
so  that  enough  chlorine  will  be  provided  to  supply  these 
organic  matters  with  what  they  require  at  once  and  to 
leave  for  a  certain  period  a  sufficient  amount  in  the  water 
to  bring  about  its  disinfection. 

The  amounts  of  chlorine  that  different  waters  will 
take  up  vary  greatly,  and  even  in  the  same  supply  the 
amount  varies  from  winter  to  summer  and  even  from 
day  to  day.  For  this  reason  highly  colored 'river  water 
may  require  several  times  as  large  a  dose  as  lake  or 
filtered  water  that  is  relatively  clean  and  colorless.  A 
dose  of  ten  pounds  per  million  gallons  may  be  sufficient 
with  the  latter.  If  a  dose  of  this  size  should  be  applied 
to  the  former  the  whole  of  the  chlorine  would  be  absorbed 


DISINFECTION. 

by  the  organic  matters  so  quickly  as  to  have  practically 
no  disinfecting  value.  On  the  other  hand,  a  dose  adapted 
to  a  water  high  in  organic  matter,  if  applied  to  a  relatively 
clean  water,  would  leave  an  excess  of  chlorine  disagreeable 
in  taste  and  odor  and  highly  objectionable  to  consumers. 

In  view  of  the  difficulty  of  adjusting  the  dose  of  chlorine 
accurately  to  all  the  varying  conditions  of  the  water 
treated,  the  plan  has  been  suggested  (and  used  to  a 
limited  extent)  of  using  a  moderate  excess  of  disinfectant, 
and  of  applying,  to  the  water  after  the  expiration  of  a 
certain  time  a  dose  of  some  harmless  substance  capable 
of  absorbing  and  removing  any  chlorine  that  may  be 
left.  Thiosulphate  of  soda  has  been  most  frequently 
used  for  this  purpose. 

Chlorine  has  a  distinct  and  disagreeable  taste  and 
smell,  and  if  too  much  of  it  is  applied  some  of  it  may 
remain  in  the  water.  As  a  practical  matter  this  rarely 
happens,  because  there  is  almost  always  organic  matter 
enough  to  take  up  the  amount  that  is  used  in  the  time 
that  elapses  before  the  water  reaches  the  consumers. 
What  does  happen  is  that  the  chlorine  acts  on  some  of 
the  organic  matters  present  in  the  water,  changing  their 
nature  so  that  they  do  produce  disagreeable  tastes  and 
smells.  There  is  more  danger  of  producing  this  result 
if  the  dose  is  large  than  if  it  is  small. 

There  is  a  great  difference  in  waters  in  this  respect. 
Some  carry  organic  matters  that  seem  capable  on  the 
slightest  provocation  of  being  changed  into  bad-smelling 
chlorine-substitution  products,  while  others  are  free  from 
such  materials  and  will  easily  carry  a  larger  dose  with 
little  risk. 


DISINFECTION  IN  CONNECTION  WITH  FILTRATION.     105 

Unfiltered  surface  waters  carry  matters  in  suspension, 
and  the  objectionable  bacteria  may  be  in  the  interior 
of  bunches  or  clots  of  suspended  matter,  where  they  will 
not  be  reached  by  the  disinfecting  action  of  the  chlorine 
during  the  period  in  which  the  chlorine  is  in  the  water. 
The  organisms  so  protected  may  remain  and  afterwards 
be  scattered  with  danger  of  carrying  any  infection  that 
may  have  been  present.  For  this  reason  the  treatment 
as  applied  to  raw  waters  is  much  less  certain  in  its  action 
than  it  is  when  applied  to  clear  filtered  waters,  even  though, 
as  is  usually  the  case,  the  applied  dose  is  much  larger. 

Disinfection  in  Connection  with  Filtration.  Disin- 
fection has  come  to  be  regarded  as  a  most  important 
auxiliary  process.  It  has  been  sometimes  used  on  the 
raw  water  going  to  the  filters  or  on  the  coagulated  water 
after  the  flow  has  settled  and  before  the  water  goes  to  the 
filters,  or  otherwise  on  the  filtered  water. 

Greater  efficiency  in  the  removal  of  objectionable 
bacteria  is  obtained  when  the  dose  is  applied  to  the  water 
after  filtration;  but  there  is  more  risk  in  producing 
tastes  and  odors  when  it  is  used  in  this  way.  When  it  is 
applied  in  advance  a  larger  dose  is  necessary,  and  the 
efficiency  obtained  is  smaller;  but  on  the  other  hand,  the 
action  of  the  filter  in  removing  and  reducing  tastes  and 
odors  produced  by  the  action  of  the  chlorine  on  the 
organic  matters  of  the  water  is  made  available ;  and  where 
the  range  between  the  minimum  dose  that  is  sufficient 
for  disinfection  and  the  maximum  dose  that  can  be  used 
without  producing  tastes  and  odors  is  narrow,  the  advan- 
tages of  the  earlier  application  are  important,  even 
though  the  utmost  efficiency  cannot  be  obtained. 


106  DISINFECTION. 

In  some  cases  disappointing  results  have  followed  the 
treatment  of  the  water  prior  to  nitration,  growing  out 
of  the  temporary  use  of  an  over-dose,  which  has  had  the 
effect  of  killing  organisms  in  the  filter  that  were  per- 
forming useful  service  in  the  process  of  purification, 
and  the  resulting  demoralization  of  the  filters. 

The  use  of  processes  of  disinfection  has  made  a  pro- 
found difference  in  the  way  in  which  other  processes  of 
purification  are  regarded.  It  has  made  it  possible  to 
secure  as  an  ordinary  working  process  to  be  carried  out 
365  days  in  the  year  a  higher  degree  of  bacterial  removal 
than  was  previously  possible;  and  on  the  other  hand, 
it  provides  a  substantial  although  not  absolute  safeguard 
against  occasional  reductions  in  the  efficiency  of  proc- 
esses that  grow  out  of  unusual  conditions  or  lack  of 
attention  on  the  part  of  the  attendants. 

Of  course  all  methods  of  disinfection  are  at  least  as 
susceptible  as  any  other  processes  to  failures  growing 
out  of  lack  of  attention  by  those  having  them  in  charge. 

Looking  at  the  matter  broadly,  the  use  of  disinfection 
has  increased  very  greatly  the  safety  of  the  water  supplies 
where  it  has  been  used. 

The  most  serious  practical  objection  to  the  use  of 
hypochlorite  of  lime  is  from  the  tastes  and  odors  frequently 
produced  by  it,  and  which  with  some  waters  seem  to  be 
unavoidable  when  adequate  doses  are  used.  The  gain 
in  hygienic  safety  resulting  from  disinfection  has  been  so 
great  that  there  is  no  thought  of  abandoning  it,  but  these 
difficulties  with  tastes  and  odors  have  been  such  as  to 
lead  to  renewed  study  of  other  methods  of  disinfection 
in  the  hope  of  finding  one  less  subject  to  this  defect. 


LIQUID  CHLORINE,  OZONE,  ETC.  107 

Liquid  Chlorine.  Liquid  chlorine  has  been  proposed 
and  is  being  used  on  a  large  scale  as  a  substitute  for 
hypochlorite  of  lime.  The  active  agent  is  the  same  as 
that  in  hypochlorite  of  lime;  and  it  may  be  assumed  that 
corresponding  quantities,  molecule  for  molecule  of  active 
material,  will  be  required. 

This  material  is  supplied  in  cylinders  under  heavy 
pressure.  At  present  prices  it  is  more  expensive  than 
an  equivalent  amount  of  hypochlorite  of  lime,  but  its 
application  is  in  some  respects  more  convenient.  It  is 
claimed  that  there  is  less  likelihood  of  producing  tastes 
and  odors  than  with  chlorine  in  the  form  of  hypochlorite 
of  lime;  but  experience  up  to  the  present  time  can  hardly 
be  considered  as  sufficient  to  fully  substantiate  this  view. 

Ozone.  The  ozone  treatment  previously  mentioned  is 
entirely  free  from  this  objection.  Waters  can  be  treated 
with  any  desired  amount,  and  if  there  is  any  change, 
improvement  in  tastes  and  odors,  and  not  deterioration,  is 
to  be  anticipated. 

In  the  past  ozone  treatment  has  been  too  expensive  for 
general  use.  Much  ingenuity  has  been  expended  in 
devising  ozonizers  of  higher  efficiency  and  arrangements 
for  bringing  the  ozonized  air  into  intimate  contact  with 
the  water  to  be  treated  by  simpler  and  less  expensive 
methods. 

Improvement  has  been  made,  and  further  improve- 
ments seem  possible.  Under  these  conditions  it  may 
be  that  ozone  will  sometime  secure  much  wider  appli- 
cation. 

Ultra-violet  Rays.  The  ultra-violet  rays  have  a  certain 
germicidal  power,  and  bacteria  may  be  killed  by  exposing 


108  DISINFECTION. 

water  in  these  layers  to  the  action  of  lamps  producing 
these  rays.  This  process  is  attractive  as  affording  a 
means  of  disinfection  without  adding  any  chemical  sub- 
stance to  the  water  and  without  any  apparent  possibility 
of  producing  disagreeable  tastes  and  odors. 

Clear  Water  Necessary.  All  the  processes  of  disinfec- 
tion to  be  efficient  require  that  the  water  to  be  treated 
should  be  free  from  suspended  matter.  In  other  words,  it 
must  be  filtered  water.  Reduction  in  numbers  of  bacteria 
may  be  obtained  by  applying  these  processes  to  raw  waters, 
especially  to  those  containing  but  little  suspended  matter, 
and  such  treatments  may  often  be  advantageous;  but  a 
clear  water  is  essential  for  obtaining  the  full  effects  of  the 
various  processes,  and  they  are  all  of  them  to  be  regarded 
as  auxiliary  processes  to  be  applied  for  the  best  results 
to  filtered  waters,  and  not  as  processes  to  be  solely  relied 
upon. 


CHAPTER  XI. 

ON  THE  APPLICATION  OF  THE  METHODS  OF  WATER 
PURIFICATION,  ARRANGED  ACCORDING  TO  THE 
MATTERS  TO  BE  REMOVED  BY  THE  TREATMENT. 

Tastes  and  Odors.  Tastes  and  odors  are  to  be  most 
frequently  found  in  waters  from  impounding  reservoirs 
and  small  lakes,  and  in  our  climate  such  waters  are  sure 
to  have  tastes  and  odors  at  times.  They  have  occurred 
even  in  those  -reservoirs  where  the  greatest  efforts  have 
been  made  to  prevent  them  by  cutting  out  shallow  flow- 
age  and  by  stripping  the  reservoir  bottoms  of  soil. 

Aeration  to  Remove  Tastes  and  Odors.  The  simplest, 
cheapest,  and  most  generally  applicable  method  of  remov- 
ing tastes  and  odors  is  by  aeration;  that  is  to  say,  by 
bringing  the  water  in  contact  with  air  by  playing  the 
water  into  it  by  fountains  or  otherwise.  The  natural 
flow  of  water  in  the  bed  of  a  mountain  stream  over  stones 
and  ledges  aerates  it  very  well.  The  exposure  of  water 
to  the  air  in  reservoirs  and  in  gently  flowing  rivers  or 
channels  certainly  tends  to  aerate  it,  but  far  less  effect  in 
removing  tastes  and  odors  is  usually  observed  from  such 
exposure. 

To  throw  water  up  in  a  fountain,  which  means  a  con- 
tact with  the  air  not  exceeding  usually  two  or  three, 
or  at  the  most,  four  seconds,  would  seem  a  very  slight 
treatment  for  water  which  has  been  exposed  to  the  wind 

109 


110  THE  APPLICATION  OF  METHODS. 

action  in  a  reservoir  for  weeks  or  months,  but  it  will 
often  do  what  the  long  exposure  has  not  accomplished. 

Among  the  cases  where  a  striking  improvement  in 
tastes  and  odors  has  followed  aeration  may  be  mentioned 
the  following: 

Ludlow  Reservoir  water,  played  through  fountains  to 
Van  Horn  Reservoir  at  Springfield,  Mass.,  in  the  summer 
of  1905.  (This  was  the  first  year  the  fountains  were  used; 
the  supply  was  filtered  in  1906.) 

Grassy  Sprain  Reservoir  water,  pumped  over  an 
aerating  device  into  the  Fort  Hill  Reservoir  at  Yonkers. 

Water  from  several  impounding  reservoirs,  let  down 
through  natural  channels  to  the  old  Croton  Reservoir 
supplying  New  York  City. 

Water  let  down  in  the  same  way  from  the  main  upper 
reservoirs  to  the  small  intake  reservoir  at  Newark. 

Such  aeration  always  reduces,  and  sometimes  removes, 
tastes  and  odors  from  the  waters  of  the  reservoirs  and 
small  lakes,  whether  resulting  from  putrefaction  in  sum- 
mer in  the  stagnant  bottom  water  or  from  growths  of 
organisms  in  the  surface  water. 

Mechanical  Filtration  to  Remove  Tastes  and  Odors. 
Mechanical  filtration  was  used  at  Wilkesbarre,  Pa.,  for 
treating  a  reservoir  water.  It  did  not  sufficiently  remove 
tastes  and  odors,  and  for  this  reason  the  plant  was  aban- 
doned. 

At  Charleston,  S.  C.,  Goose  Creek  water,  which  is  sub- 
ject to  very  bad  tastes  and  odors,  is  successfully  purified 
by  a  process  of  which  mechanical  filtration  is  one 
step. 


Aeration  of   Missouri   River  Water    in   passing  from   one   settling 
basin  to  another  at  Omaha,  Neb. 


Aeration  of  water  in  falling  over  a  stone  dam. 


/'v>:^  l  ** 


SAND  FILTRATION.  Ill 

The  whole  process  consists  of  the  following: 

(1)  Use  of  copper  sulphate  in  the  reservoir  to  hold 
down  growths  of  organisms. 

(2)  Aeration  of  the  water. 

(3)  Coagulation,  followed  by  passage  through  a  basin 
holding  two  days'  supply. 

(4)  Aeration  of  the  water  on  leaving  the  basin. 

(5)  Mechanical  nitration. 

(6)  Aeration  on  leaving  the  niters. 

In  the  above  process  the  three  aerations  were  not  used 
at  first,  and  without  them  the  tastes  and  odors  were  not 
removed.  The  addition  of  the  aeration  at  the  places  as 
stated  served  to  make  the  process  reasonably  efficient. 

In  general  it  may  be  stated  that  mechanical  filtration 
is  not  efficient  in  removing  tastes  and  odors.  Probably 
in  most  cases  when  improvements  have  followed  it,  they 
have  resulted  more  from  the  incidental  aerations  than 
from  the  filtration. 

Sand  Filtration  to  Remove  Tastes  and  Odors.  Sand 
filtration  has  considerable  power  of  reducing,  and  in 
some  cases  of  removing,  tastes  and  odors,  but  it  is  not 
usually  to  be  wholly  relied  upon  when  the  raw  water  is 
very  bad. 

In  England  it  is  used  for  treating  water  from  impound- 
ing reservoirs,  and  seems  to  be  usually  efficient  in  remov- 
ing such  tastes  and  odors  as  there  are;  but  these  tastes 
and  odors  clearly  are  far  less  serious  than  those  in  many 
or  most  American  reservoir  waters. 

At  Reading,  Pa.,  with  impounding  reservoir  waters, 
subject  to  moderate  but  not  extreme  tastes  and  odors, 


H2  THE  APPLICATION  OF  METHODS. 

filtration  at  a  rate  of  from  3,000,000  to  5,000,000  gallons 
per  acre  daily  is  sufficient. 

At  Springfield,  Mass.,  experiments  indicated  that  such 
filtration,  even  when  accompanied  by  aeration,  would 
not  suffice  to  deodorize  the  water  from  Ludlow  Reservoir, 
which  is  exceptionally  bad.  In  this  case  putting  the  water 
through  two  filters  in  succession,  with  aeration  before, 
between,  and  after,  did  serve  to  fully  remove  the  odors. 

Intermittent  Filtration  to  Remove  Tastes  and  Odors. 
Intermittent  filtration  is  a  term  applied  to  filters  of  special 
construction  and  operation.  The  filters  are  usually 
drained  at  the  bottom  and  the  outlets  are  always  open  to 
let  any  water  that  gets  through  the  filter  sand  flow  away 
without  obstruction.  The  water  to  be  filtered  is  applied 
rapidly  to  the  surface  at  intervals,  with  periods  of  rest 
between,  during  which  the  surface  of  the  filtering  ma- 
terial is  exposed  to  the  air,  and  the  sand  becomes  drained. 
The  sand  is  preferably  rather  coarser  than  would  tie  used 
in  ordinary  filtration. 

Intermittent  filtration  has  been  particularly  successful 
in  purifying  sewage.  It  is  also  used  for  treating  manu- 
facturing wastes  containing  much  organic  matter.  It  is 
successful  for  these  purposes  because  it  brings  the  organic 
matter  in  the  liquid  in  contact  with  more  air,  and  in  more 
intimate  contact  with  air,  and  for  a  longer  time,  in  the 
pores  of  the  sand  than  can  be  secured  in  any  other  way. 
This  contact  is  essential  for  the  oxidation  of  the  organic 
matter. 

The  reason  why  ordinary  or  continuous  sand  filtration 
failed  to  remove  odors  in  the  Springfield  tests  seemed 


Intermittent  filters  at  Springfield,  Mass.,  showing  one  filter  out 
use  and  being  cleaned. 


Intermittent  filters  at  Springfield,  Mass.,  showing  aeration  of  water 
at  entrance  and  the  distribution  of  the  water  to  the  four  filters. 


INTERMITTENT  FILTRATION.  113 

clearly  to  be  that  water  carried  more  organic  matter 
than  could  be  disposed  of  by  all  the  oxygen  present, 
including  that  furnished  by  the  aeration. 

It  seemed  reasonable  to  suppose  that  if  more  air  could 
be  brought  in  contact  with  this  water  the  process  might 
be  made  successful,  and  the  method  of  intermittent  ni- 
tration successfully  used  for  this  purpose  in  sewage  puri- 
fication appeared  to  be  the  best  way  of  accomplishing 
this  end. 

The  condition  of  the  water  at  Springfield  being 
extremely  unsatisfactory,  this  process  seemed  worthy  of  a 
trial.  The  local  conditions  proved  exceptionally  favor- 
able for  the  construction  of  this  kind  of  filters.  A  bank 
of  sand  close  to  the  reservoir  was  found  which  was  of 
such  a  quality  that  it  could  be  used  just  as  it  came  from 
the  bank  for  filter  sand. 

This  was  leveled  off  to  form  a  filtering  area  of  about 
four  acres.  This  was  underdrained.  No  water-tight 
bottom  was  provided.  Expense  was  thus  saved,  though 
some  water  was  lost,  seeping  back  to  the  reservoir.  A 
pumping  station  lifted  the  water  to  an  aerator,  from  which 
it  flowed  through  gates  to  the  four  divisions  of  the  filters. 
The  pump  was  operated  about  16  hours  daily,  the  filters 
being  left  to  drain  for  the  other  eight.  The  plant  was 
built  for  temporary  use  only  and  is  no  longer  used  for  the 
Springfield  supply,  as  the  city  is  now  furnished  with  water 
from  a  new  and  larger  source.  It  cost  $50,000  to  build, 
and  yielded  about  12,000,000  gallons  a  day  of  water  sub- 
stantially free  from  tastes  and  odors,  and  otherwise  im- 
proved in  quality.  The  cost  of  operation,  that  is  to  say, 


114  THE  APPLICATION  OF  METHODS. 

of  pumping  the  water,  of  caring  for  the  filters  and  renew- 
ing the  surface  sand,  and  of  maintaining  a  small  labor- 
atory, which  was  necessary  for  the  operation,  with  super- 
vision, was  five  or  six  dollars  per  million  gallons. 

This  plant  was  not  capable  of  operation  in  winter,  and 
it  was  not  expected  to  have  a  high  bacterial  efficiency,  and 
it  would  not  therefore  do  for  use  where  the  water  was 
subject  to  pollution. 

Intermittent  filtration  probably  has  no  advantage  over 
ordinary  sand  filtration  with  thorough  aeration  in  remov- 
ing tastes  and  odors,  in  those  cases  where  the  amount  of 
organic  matters  associated  with  them  are  not  excessive; 
that  is  to  say,  where  they  do  not  exceed  the  amounts  which 
the  air  present  in  such  filtration  is  able  to  dispose  of. 

But  where  the  water  is  very  bad  indeed,  intermittent 
filtration  with  aeration  is  perhaps  the  most  powerful 
method  at  our  disposal  for  removing  tastes  and  odors. 
The  only  alternative  is  the  use  of  successive  filtrations 
with  aeration  between. 

Color.  The  word  color  refers  to  soluble  yellow  color- 
ing matter  extracted  from  dead  leaves,  peat,  and  other 
vegetable  matters,  and  it  is  principally  found  in  swamp 
waters.  As  previously  stated,  it  is  found  in  many  im- 
pounding reservoir  waters  and  in  river  waters  in  certain 
parts  of  the  country. 

Color  is  not  ordinarily  removed  to  any  considerable 
extent  by  simple  filtration  through  either  sand  or  me- 
chanical filters. 

Color  is  slowly  bleached  and  destroyed  by  sunshine. 
In  large  impounding  reservoirs  this  is  often  a  matter  of 


COLOR.  "5 

importance,  but  the  action  is  too  slow  to  be  considered  in 
artificial  purification. 

Ozone  destroys  color.  If  it  were  not  for  the  large  cost 
of  producing  the  ozone,  this  would  be  a  most  desirable 
method  of  removing  it. 

Color  is  rendered  insoluble  by  certain  coagulants  and 
therefore  capable  of  removal  by  filtration.  Sulphate 
of  alumina  is  most  commonly  and  successfully  used  for 
this  purpose,  and  this  is  at  present  the  usual  and  most 
feasible  way  of  removing  it. 

There  are  a  great  many  filter  plants  treating  water  that 
is  more  or  less  colored,  with  sulphate  of  alumina,  and 
successfully  removing  most  of  the  color.  Among  these 
the  following  may  be  mentioned. 

Norfolk,  Va.,  where  a  very  highly  colored  water  from 
small  lakes  and  streams  is  used.  This  water  is  coagu- 
lated, stored  in  a  natural  basin  to  allow  the  action  to 
become  completed,  and  is  then  passed  through  mechani- 
cal filters  of  the  so-called  Jewell  type. 

Charleston,  S.  C.,  where  the  water  is  treated  as  pre- 
viously described  in  connection  with  tastes  and  odors. 
The  sulphate  of  alumina  used  in  the  treatment  serves  to 
decolorize  the  water.  As  there  is  not  enough  alkalinity 
naturally  present  in  Goose  Creek  water  to  react  with  the 
coagulant  and  to  combine  with  the  acid  constituent  of  it, 
lime  is  added  to  the  water  in  sufficient  amount  to  do  this. 
The  lime  so  added  does  not  act  as  does  lime  added  to  a 
naturally  hard  water.  There  is  no  precipitation  of  lime. 
The  whole  amount  added  remains  in  solution  and  makes 
the  water  so  much  harder. 


Il6  THE  APPLICATION  OF  METHODS. 

Watertown,  N.  Y.,  where  Black  River  water  is  coag- 
ulated with  sulphate  of  alumina,  and  is  then  filtered 
through  mechanical  filters.  Soda  ash  is  used  to  make 
up  deficiency  in  alkalinity  on  the  few  days  in  the  year 
that  it  is  necessary.  . 

All  the  above  mentioned  waters  are  very  highly  colored 
and  are  satisfactorily  decolorized  by  the  treatment.  If 
smaller  plants  and  less  deeply  colored  waters  were  in- 
cluded, the  list  could  be  indefinitely  extended. 

The  use  of  iron  sulphate  with  lime  in  place  of  sul- 
phate of  alumina  has  been  tried,  especially  at  Quincy 
and  Moline,  111.;  but  for  color  removal  this  treatment 
appears  to  be  clearly  less  satisfactory  than  the  usual  sul- 
phate of  alumina  treatment. 

Fermentation  of  Coloring  Matter  in  the  Stagnant  Bot- 
tom Water  of  Impounding  Reservoirs.  When  highly 
colored  water  is  stored  in  an  impounding  reservoir,  and 
the  bottom  water  goes  through  the  putrefaction  process, 
it  does  not  directly  reduce  the  color  of  the  water,  but  it 
does  change  the  chemical  nature  of  the  coloring  material 
in  such  a  way  that  it  may  afterwards  be  removed  to  a 
considerable  extent  by  filtration  without  chemical  treat- 
ment. 

The  river  waters  filtered  without  coagulation  at  Law- 
rence, Albany,  and  many  other  places,  are  more  or  less 
colored.  And  some  of  this  color  is  always  removed  by 
the  filtration.  The  amount  of  removal  ranges  from  a 
fifth  to  a  third.  As  a  general  average  a  reduction  of 
25  per  cent  is  obtained.  And  in  the  filtration  of  reser- 
voir waters  that  have  not  been  through  the  putrefactive 


>> 

o 


FERMENTATION  OF  COLORING  MATTER.          117 

process  about  the  same  proportion  of  removal  is  ob- 
tained. 

On  the  other  hand,  highly  colored  waters  from  deep 
reservoirs  are  often  easily  and  almost  completely  decol- 
orized. In  visiting  the  Rivington  works  of  the  city  of 
Liverpool  in  1896,  the  writer  was  deeply  impressed  with 
the  almost  complete  removal  of  the  high  color  of  the  res- 
ervoir water  by  simple  nitration  through  ordinary  sand 
niters.  In  the  experiments  at  Springfield  on  the  Ludlow 
Reservoir  water  to  remove  tastes  and  odors  a  very  high 
degree  of  color  removal  was  obtained,  and  the  filters 
since  built  to  deodorize  the  water  also  serve  to  decolorize 
it  to  an  extent  that  would  be  altogether  impossible  with 
river  water  or  with  reservoir  water  which  had  not  been 
subject  to  putrefaction. 

At  Charleston,  S.C.,  with  Goose  Creek  water,  coag- 
ulant is  used,  but  the  amount  required  to  decolorize  the 
water  is  much  less  than  would  be  necessary  for  the  treat- 
ment of  a  river  water  of  equal  color.  In  this  case  it  is 
to  be  noted  that  Goose  Creek  Reservoir  is  far  too  shallow 
to  have  a  permanent  stagnant  layer;  but  nevertheless 
very  strong  putrefaction  changes  do  take  place  in  the 
water  near  the  bottom.  This  water  which  has  putre- 
fied is  mixed  by  the  wind  with  top  water  from  time  to 
time,  and  the  whole  body  of  water  has  to  a  large  extent 
the  character  of  bottom  water  from  a  deep  reservoir, 
and  at  the  same  time  it  contains  the  organisms  usual  in 
top  water. 

The  putrefaction  may  bring  about  some  changes  in 
the  coloring  matter  itself,  which  renders  it  more  easy  of 


Il8  THE  APPLICATION  OF  METHODS. 

removal,  but  the  principal  cause  of  the  change  in  char- 
acter seems  to  be  associated  with  the  condition  of  the 
iron  that  is  always  present  in  these  waters.  During  the 
putrefaction  the  oxygen  dissolved  in  the  water  is  exhaus- 
ted, and  the  iron  is  reduced  from  the  ferric  to  the  ferrous 
state.  Iron  is  freely  taken  into  solution  under  these 
conditions  from  the  materials  of  the  bottom  of  the  reser- 
voir, and  these  are  pretty  sure  to  contain  a  sufficient 
supply  of  it.  The  bottom  stagnant  water  of  reservoirs 
nearly  always  contains  far  more  iron  than  the  water 
entering  the  reservoir. 

Now  when  this  water  is  aerated  the  iron  is  oxidized 
again  to  the  insoluble  ferric  state.  If  there  is  enough 
iron  present  in  proportion  to  the  coloring  matter,  it  will 
precipitate  out  forthwith.  In  doing  this  it  acts  as  a 
coagulant  upon  the  coloring  matter  and  removes  it.  If 
the  amount  of  iron  is  small  in  proportion  to  the  coloring 
matter,  then  the  organic  matter  will  hold  the  iron  in 
solution  even  in  the  ferric  state;  but  the  combination  is 
not  quite  stable  and  is  easily  broken  up.  It  is  more 
likely  to  be  broken  up  and  removed  in  a  filter  than  in  a 
reservoir.  There  are  three  possible  conditions  resulting 
from  the  putrefaction  followed  by  aeration,  depending 
upon  the  relative  amount  of  iron  and  coloring  matter, 
and  how  far  the  putrefaction  has  gone,  namely  (i)  there 
may  be  an  immediate  flocculent  precipitate,  such  as 
would  be  thrown  down  by  sulphate  of  alumina;  or  (2) 
the  water  may  show  no  physical  change,  but  still  be  in 
condition  where  the  matters  will  be  removed  by  filtration 
without  further  preliminary  treatment;  or  (3)  the  com- 


TURBIDITY.  IIQ 

bination  of  iron  and  organic  matter  may  be  too  stable 
for  removal  by  nitration;  but  it  has  nevertheless  be^-p  so 
far  changed  that  it  can  be  removed  by  a  smaller  amoimx 
of  coagulant  than  would  otherwise  be  necessary  for  the 
removal  of  the  coloring  matter. 

The  action  of  iron  in  reservoirs,  its  accumulation  and 
separation  after  aeration,  were  studied  by  the  late  Dr. 
T.  M.  Drown,  and  by  Mr.  Desmond  FitzGerald  and 
others  in  Boston,  especially  about  1890-93,  and  became 
fully  understood  at  that  time;  but  more  than  ten  years 
elapsed  before  practical  advantage  of  these  actions  was 
taken  in  decolorizing  water.  In  England,  it  is  true, 
it  plays,  and  for  many  years  has  played,  an  important 
part  in  cleaning  reservoir  waters;  but  .this  seems  to 
have  been  rather  accidental  than  intentional,  and  there 
seems  to  be  no  reason  to  believe  that  the  process  was 
ever  thoroughly  understood  or  that  efforts  were  made 
to  facilitate  it. 

It  is  probable  that  in  future  much  more  extended  use 
will  be  made  of  this  method  of  decolorization  of  reservoir 
waters,  especially  as  the  treatment  is  also  substantially 
that  adapted  in  the  removal  of  odors  and  tastes  from 
these  waters,  and  the  two  objects  are  thus  secured  by  the 
same  treatment. 

Turbidity.  Practically  the  turbidity  question  may  be 
limited  to  river  waters.  Lake  and  reservoir  waters  are 
occasionally  turbid,  but  seldom  in  a  way  to  be  seriously 
troublesome,  or  to  such  an  extent  that  they  cannot  be 
cleaned  by  methods  of  treatment  which  might  be 


120  THE  APPLICATION  OF  METHODS. 

adapted  to  purify  the  waters  in  other  respects.  All 
river  waters  are  more  or  less  turbid  at  times,  but  the 
differences  between  different  river  waters  are  very  great 
indeed. 

In  a  general  way  the  turbidity  question  is  not  a  diffi- 
cult one  in  that  part  of  the  United  States  which  was  once 
covered  with  glaciers.  South  of  this  area  turbidity  is  of 
such  importance  as  practically  to  control  the  methods  of 
treatment  that  must  be  used.  This  division  obviously 
is  a  rough  one,  with  many  exceptions  both  ways,  but  it 
does  represent  the  predominating  conditions. 

The  conditions  in  the  northern  or  glaciated  area  corre- 
spond more  nearly  with  European  conditions,  and  it  is 
in  this  area  only  that  comparisons  with  European  prac- 
tice are  helpful. 

In  water  purification  there  are  two  matters  to  be  ascer- 
tained as  to  turbidity.  First,  how  much  turbidity  is  pres- 
ent in  the  water ;  and  second,  how  small  are  the  particles 
that  constitute  it. 

If  the  turbidity  is  sufficiently  coarse  grained,  it  can  be 
removed  by  sand  filtration  without  previous  chemical 
treatment.  If  it  is  present  in  large  amounts,  it  can  be 
cheaply  removed  in  part  in  settling  basins,  and  in  this 
way  the  work  of  the  filters  can  be  lightened,  and  the  cost 
reduced.  And  that  work  can  be  still  further  lightened 
by  the  use  of  preliminary  or  roughing  filters,  which  do 
the  work  of  sedimentation  basins,  but  perhaps  more 
quickly  and  more  thoroughly. 

Much  of  the  turbidity  of  certain  northern  rivers  is  of 
this'  coarse-grained  variety,  but  it  is  seldom  present  in 


TURBIDITY.  121 

large  amounts,  or  continuously;  and  when  it  is  only  pres- 
ent once  in  awhile,  investment  in  roughing  niters  or  even 
in  sedimentation  basins  may  be  of  doubtful  economic 
value.  It  is  very  easy  to  spend  on  such  works  more  than 
can  possibly  be  saved  in  the  cost  of  the  subsequent 
filter  operation. 

Altogether  the  coarse-grained  turbidity  does  not  pre- 
sent a  very  serious  problem  in  water  purification. 

In  that  part  of  the  country  which  was  not  glaciated, 
and  this  includes  the  lower  Susquehanna  basin,  much 
of  the  Ohio  basin,  and  the  Missouri  basin,  and  all  to 
the  south  of  them,  turbidity  is  often  present  in  large 
amounts,  and  it  is  usually  composed  of  extremely  fine 
grains,  and  the  water  often  runs  turbid  in  the  streams 
continuously  for  weeks  and  even  for  months  at  a  time. 
In  fact  there  are  some  rivers  of  which  the  waters  are 
nearly  always  turbid. 

There  is  one  known  way  of  removing  turbidity  from 
these  waters,  and  only  one;  that  is  by  coagulation 
or  chemical  precipitation. 

Without  such  treatment,  no  amount  of  filtration,  single 
or  double,  or  multiple,  will  remove  it.  With  such  chem- 
ical treatment  adequately  carried  out,  the  simplest  and 
easiest  filtration  will  suffice  to  make  the  most  refractory 
water  as  clean  as  distilled  water. 

There  are  a  number  of  chemical  treatments  that,  are 
used,  according  to  habit  and  other  circumstances.  These 
are  all  closely  related  to  each  other,  and  are  frequently 
combined  to  a  greater  or  less  extent  so  that  strict  classi- 
fication is  not  possible. 


122  THE  APPLICATION  OF  METHODS. 

The  substance  first  and  most  generally  used  for  this 
treatment  is  sulphate  of  alumina. 

When  the  amount  of  lime  naturally  present  in  the 
water  is  not  sufficient  to  effect  a  complete  reaction  with 
it,  lime  must  be  added  in  connection  with  its  use.  Soda 
ash  may  be  used  in  place  of  lime,  at  somewhat  greater 
expense,  but  with  the  advantage  that  the  water  is  not 
hardened.  Generally,  however,  there  is  enough  lime 
present  for  the  reaction  in  excessively  turbid  waters,  and 
the  use  of  lime  for  this  purpose  is  not  very  common. 

Sulphate  of  iron,  or  copperas,  is  also  extensively  and 
successfully  used  in  treating  turbid  waters.  A  greater 
degree  of  alkalinity  is  required  to  precipitate  this  sub- 
stance, and  lime  must  always  be  used  in  connection  with 
it  And  by  using  more  lime,  some  of  the  lime  naturally 
present  in  the  water  can  be  thrown  down  together  with 
that  added,  thereby  softening  the  water  as  well  as  remov- 
ing the  turbidity  from  it. 

Under  some  conditions  it  would  seem  that  the  pre- 
cipitation of  the  lime  and  magnesia  of  the  water  by  lime 
alone  would  at  once  soften  it  and  suffice  to  coagulate  the 
turbidity,  but  it  does  not  seem  likely  that  this  reaction 
can  often  be  fully  depended  upon.  The  lime  and  mag- 
nesia precipitates  do  not  have  as  great  a  coagulating 
value  as  those  of  iron  and  alumina. 

Lime  and  iron  are  cheaper  than  sulphate  of  alumina, 
and  there  are  great  advantages  in  their  use  in  large  plants. 
Their  application  is  much  more  difficult  to  control  ade- 
quately, and  it  should  not  be  undertaken  except  with  the 
assistance  of  a  competent  resident  •  chemist  and  good 


SOFTENING.  123 

appliances  for  adding  the  lime  in  any  quantity  that  may 
be  required  by  the  composition  of  the  water. 

This  method  of  treatment  leaves  the  water  with  an 
unnatural  deficiency  of  carbonic  acid.  It  is  necessary 
that  the  carbonic  acid  should  be  absent  to  allow  the  reac- 
tions to  take  place  which  result  in  the  coagulation.  But 
there  is  a  question  as  to  the  desirability  of  supplying 
water  for  use  in  this  condition.  Such  water  always  tends 
to  deposit  a  coating  of  lime  upon  everything  with  which 
it  comes  in  contact.  This  is  more  apt  to  be  the  case 
where  the  coagulating  basins  in  which  the  reactions  take 
place  are  not  very  large. 

It  has  usually  been  thought  necessary  to  restore  to  the 
water  a  normal  amount  of  carbonic  acid  at  the  end  of 
the  process.  This  is  done,  for  example,  at  the  softening 
plant  at  Winnipeg,  by  burning  coke  and  allowing  the 
water  to  fall  a  short  distance  through  a  space  containing 
the  products  of  combustion  of  the  coke,  of  which  products 
of  course  carbonic  acid  gas  is  the  important  one. 

At  St.  Louis  the  water  is  subjected  to  the  iron  and 
lime  treatment,  followed  by  subsidence  in  large  basins, 
in  which  the  bulk  of  the  precipitate  settles.  The  par- 
tially purified  water  is  then  sent  to  the  city  without  filtra- 
tion or  recarbonating,  or  other  treatment.  While  the 
result  is  very  far  from  ideal,  the  improvement  over  pre- 
vious conditions  is  so  marked  as  to  be  generally  satisfac- 
tory. 

Softening.  Softening  in  connection  with  the  treatment 
of  turbid  river  waters  has  just  been  mentioned.  Ground 
waters  are  also  softened.  In  fact,  up  to  the  present  time 


124  THE  APPLICATION  OF  METHODS. 

most  of  the  softening  that  has  been  done  has  been  of 
ground  water. 

The  method  is  that  of  the  old  Clark  process.  The 
lime  of  the  water  is  precipitated  by  other  lime  that  is 
added  to  the  water  for  that  purpose,  and  the  resulting 
precipitate  of  carbonate  of  lime  is  settled,  strained,  or 
filtered  from  the  water.  There  are  many  appliances  for 
carrying  out  this  process.  Most  of  them  are  specially 
adapted  to  moderately  small  plants,  such  as  those  soften- 
ing water  for  boiler-feed  purposes.  Such  plants  have  been 
extensively  installed  by  the  railroads  in  some  parts  of 
the  country,  and  also  by  manufacturing  establishments. 

Winnipeg,  Canada,  has  the  most  important  municipal 
plant  in  America  for  softening  ground  water.  Oberlin, 
Ohio,  softens  reservoir  water.  In  addition  there  are  the 
plants  which  in  connection  with  other  treatments  partially 
soften  river  waters. 

Iron  Removal.  Iron  is  troublesome  only  in  ground 
waters.  Its  removal  is  a  distinct  process,  rarely  com- 
bined with  purification  for  any  other  purpose.  In  most 
cases  the  iron  can  be  removed  with  such  ease  and  with 
such  simple  appliances  that  the  purification  is  easier  and 
cheaper  than  any  other  water  treatment  except  the  re- 
moval of  odors  by  aeration. 

It  is  simply  necessary  to  thoroughly  aerate  the  water 
to  remove  the  excess  of  carbonic  acid,  and  introduce  the 
oxygen  needed  to  oxidize  the  iron  from  the  soluble  ferrous 
state  in  which  it  exists  in  the  water,  to  the  insoluble  ferric 
state.  It  can  then  be  removed  by  filtration.  The  pre- 
cipitated iron  is  very  easily  removed,  and  the  filtration 


Interior  of  Mechanical  Filter  Plant,  Minneapolis. 


Softening  plant  for  reservoir  water  at  Oberlin,  Ohio. 
Courtesy  of  Mr.  W.  B.  Gerrish. 


REMOVAL  OF  THE  EFFECTS  OF  SEWAGE  POLLUTION.  125 

may  be  rather  rapid,  and  the  appliances  simple  and 
inexpensive. 

Occasionally,  as  at  Reading,  Mass.,  and  at  Superior, 
Wis.,  the  iron  is  held  more  firmly  in  solution  in  some 
unknown  way  and  will  not  separate  so  easily.  In  these 
cases  either  one  must  be  contented  with  a  partial  removal 
(which  may,  however,  answer  practically  very  well)  or 
more  vigorous  chemical  treatment  must  be  given. 

Removal  of  the  Effects  of  Sewage  Pollution  The 
problem  of  removing  the  effects  of  sewage  pollution  from 
a  water  by  artificial  purification  is,  from  a  sanitary  stand- 
point, the  most  important  of  all,  and  the  one  that  occurs 
most  widely.  It  is  also  the  one  which  has  been  longest 
and  most  carefully  studied  and  in  regard  to  which  there 
is  the  most  information. 

Sewage  pollution  is  most  important  in  river  supplies, 
as  practically  all  large  river  waters  are  more  or  less 
subject  to  it.  It  is  also  important  in  many  or  most  sup- 
plies from  large  lakes.  It  is  far  less  important  for  sup- 
plies from  small  lakes  and  impounding  reservoirs,  but 
even  in  such  cases  there  is  often  population  upon  the 
catchment  areas  which  makes  it  worth  while  in  selecting 
a  method  of  purification  to  get  one  that  is  capable  of 
dealing  with  the  effects  of  sewage  pollution. 

This  can  be  done  without  difficulty.  The  methods  of 
purification  adapted  to  the  removal  of  turbidity  and  color 
are  also  adapted  to  bacterial  or  hygienic  efficiency,  al- 
though many  precautions  must  be  taken  which  would 
be  unnecessary  if  there  were  no  hygienic  conditions  to 
be  met. 


126  THE  APPLICATION  OF  METHODS. 

Sand  Filtration,  for  the  Removal  of  the  Effects  of  Sewage 
Pollution.  B  On  the  whole,  the  best  results  in  water  puri- 
fication, as  measured  by  the  improvement  in  the  health 
and  the  reduction  of  the  death  rate  among  those  who  use 
the  water,  have  been  obtained  with  sand  filters.  This 
is  probably  because  the  method  is  an  old  one,  has  been 
long  and  carefully  studied,  and  has  been  applied  on  a 
large  scale  in  well  perfected  forms  for  many  years,  rather 
than  to  any  natural  superiority  of  the  method.  There 
are  also  cases  where  inadequate  purification  has  been 
obtained  by  this  method,  resulting  from  defective  con- 
struction or  from  defective  operation,  where  sickness  and 
death  have  resulted.  But  such  cases  have  not  occurred 
in  plants  of  the  better  class  which  are  carefully  operated. 

Mechanical  Filtration,  for  the  Removal  of  the  Effects 
of  Sewage  Pollution.  Most  of  the  mechanical  niters 
now  in  use  in  America  have  fallen  very  far  short  in 
hygienic  efficiency.  The  greater  part,  of  them  are  of 
old  and  inferior  types. 

Even  with  these  old  plants  with  skilful  manipulation 
it  is  often  possible  to  get  fairly  good  results;  but  these 
older  plants  have  seldom  had  skilful,  and  often  not 
even  intelligent,  manipulation;  and  it  is  no  wonder  that 
they  have  so  often  fallen  short  of  what  was  expected  of 
them.  It  is  rather  to  be  wondered  that  with  the  appli- 
ances and  men  that  have  been  used,  so  much  has  been 
accomplished  with  them. 

All  the  larger  and  more  recent  plants  of  this  type  have 
besn  equipped  with  many  devices  for  performing  the 
various  operations  better  than  was  formerly  possible,  and 


General  View  of  Washington  Filters.    The  filters  are  covered  and  the 
top  is  grassed  over  and  used  as  a  park. 


Interior   view  of   a   filter   at  Washington,   showing  the  hydraulic 
removal  of  the  surface  layer  of  dirty  sand. 


HYGIENIC  EFFICIENCY.  127 

also  for  doing  them  more  certainly;  and  in  these  newer 
and  better  plants  it  has  been  customary  to  install  a  labo- 
ratory and  to  employ  a  superintendent  of  experience  in 
operating  niters  and  training  in  hygiene  and  bacteri- 
ology, to  ascertain  what  is  being  done  at  all  times. 

This  supervision  has  led  to  great  improvements  in 
methods,  which  were  only  possible  through  close  and 
continued  study  under  the  actual  conditions  of  operation; 
and  it  has  done  more  than  all  else  to  insure  regularly 
good  results. 

At  present  the  mechanical  filters  of  the  country  that 
have  been  constructed  and  operated  in  this  way  are  doing 
as  good  work,  measured  by  bacterial  efficiency,  as  the 
corresponding  sand  filter  plants;  and  there  is  reason  to 
believe  that  in  time  the  death  rate  data  will  show  corre- 
sponding results  from  them. 

Other  Methods  of  Purification  for  Hygienic  Efficiency. 
The  hygienic  efficiency  of  other  methods  of  purification 
need  be  mentioned  only  in  a  very  brief  way. 

Intermittent  filtration,  as  used  at  the  Ludlow  Reservoir, 
Springfield,  Mass.,  has  considerable  power  of  bacterial 
purification,  but  is  by  no  means  equal  in  this  respect  to 
filters  of  standard  construction.  The  same  may  be  said 
of  the  processes  of  iron  removal  by  aeration  and  rapid 
filtration,  but  in  this  case  the  bacterial  efficiency  will  be 
greater  as  the  amount  of  iron  is  greater  and  exerts  a 
greater  coagulating  effect  upon  whatever  suspended  mat- 
ter, including  the  bacteria,  there  may  be  in  the  water. 

There  is  no  reason  to  believe  that  the  preliminary  filtra- 
tion or  scrubbing  of  water,  to  be  afterward  passed  through 


128  THE  APPLICATION  OF  METHODS. 

sand  filters,  contributes  to  any  substantial  extent  to  the 
efficiency  of  the  process  as  a  whole,  precisely  as  there  is 
no  reason  for  believing  that  it  makes  any  great  difference 
with  the  passage  of  finely  divided  turbidity  through  the 
final  filters. 

Hygienic  Standards  of  Purification.  Before  the  recent 
great  extension  in  the  use  of  methods  of  disinfection, 
there  was  a  well-marked  tendency  for  water  purification 
methods  to  crystallize  about  certain  standards.  These 
standards  were  those  in  the  different  methods  which 
served  to  reduce  the  turbidity  and  color  to  inappreciable 
amounts,  and  which,  in  general,  removed  something 
like  99  per  cent  of  the  bacteria  when  those  organisms 
resulting  from  sewage  pollution  were  fairly  numerous 
in  the  water.  Such  filtration,  in  a  general  way,  cost, 
including  all  operating  expenses  and  5  per  cent  on  the 
required  capital,  something  like  $10  per  million  gallons 
of  water  treated.  There  was  no  final  reason  for  such 
standards.  They  were  adopted  by  consent  because 
they  represented  a  purification  that  was  reasonably 
satisfactory  and  that  could  be  reached  at  a  cost  that 
was  not  burdensome. 

Such  purification  made  the  waters  of  some  of  the  most 
highly  polluted  rivers  used  for  public  water  supplies 
in  the  United  States,  as  for  example,  the  Merrimack 
and  Hudson,  as  safe  hygienically,  and  as  satisfactory 
in  every  way,  as  supplies  drawn  from  better  sources 
so  far  as  the  results  can  be  measured  by  the  best  means 
at  our  disposal,  namely,  by  bacterial  tests  and  by  the 
records  of  the  health  departments  of  the  various  cities 


HYGIENIC  STANDARDS  OF  PURIFICATION.        I2Q 

where  the  waters  were  used.  It  is  true  that  the  most 
searching  bacterial  methods  disclosed,  in  such  purified 
waters  (as  in  relatively  unpolluted  but  unfiltered  surface 
waters),  some  bacteria  characteristic  of  sewage  and 
undoubtedly  derived  from  it. 

The  use  of  methods  of  disinfection  has  changed  these 
standards  radically.  By  their  use  it  has  been  found 
possible  to  remove  most  of  the  remaining  bacteria  so  that 
the  water  supplied  can  be  as  easily  and  certainly  held 
within  one-tenth  of  one  per  cent  of  those  in  the 
raw  water,  as  it  formerly  could  be  held  within  one  per 
cent.  In  other  words,  nine-tenths  of  whatever  danger 
there  may  have  been  hi  the  filtered  water  can  now  be 
removed  by  this  supplementary  process  at  a  cost  so  small 
as -to  add  but  little  to  the  whole  cost  of  purification.  In 
fact,  the  efficiency  with  disinfection  is  frequently  so  great 
as  to  make  it  permissible  to  omit  certain  precautions 
formerly  thought  necessary  in  connection  with  filters, 
and  so  to  reduce  the  cost  of  filtering  until  the  whole  cost 
of  the  treatment  may  be  less  instead  of  greater  than 
before. 

When  the  conditions  of  1913  are  compared  with  those 
of  ten  years  earlier,  there  has  been  an  increase  in  the 
population  of  cities  discharging  sewage  to  water  courses 
and  lakes  and  an  increase  in  the  pollution  of  the  waters. 
On  the  other  hand,  the  general  introduction  of  methods 
of  disinfection,  improvements  in  methods  of  chemical 
treatment  and  in  other  auxiliary  processes,  and  improve- 
ments in  the  art  of  filtering,  have  made  it  possible  to 
produce  filtered  supplies  of  greater  purity  and  safety 
from  a  hygienic  standpoint  than  could  possibly  have  been 


130  THE  APPLICATION  OF  METHODS. 

produced  at  the  earlier  date.  In  this  interval,  looking 
at  the  matter  broadly,  there  has  been  a  constant  and 
rapid  improvement  in  the  qualities  of  public  water  sup- 
plies of  the  country,  notwithstanding  the  increased  pollu- 
tion of  the  sources. 

Even  to-day  the  limit  has  not  been  reached.  It  may  be 
admitted  that  the  time  will  come  when  a  still  higher 
degree  of  bacterial  efficiency  will  be  required.  Present 
conditions  do  not  seem  to  demand  it,  but  we  must  expect 
that  in  some  time  in  the  future  conditions  will  arise 
which  will  make  it  necessary.  When  additional  purifica- 
tion is  required  it  can  be  furnished. 

There  are  many  ways  in  which  it  can  be  secured.  It 
will  be  enough  to  mention  the  use  of  lower  rates  of 
filtration,  of  filtering  materials  with  finer  grains,  of  more 
complete  chemical  preparation,  and  of  more  complete 
final  disinfection  by  processes  that  are  harmless  and  that 
do  not  injure  the  water. 

It  is  idle  to  attempt  to  decide  now  how  the  problem 
can  best  be  solved  when  it  arises.  Even  to-day,  with  the 
limit  of  cost  raised  so  that,  for  example,  the  cost  of  the 
whole  process  of  purification  might  be  raised,  let  us  say, 
to  $20  per  million  gallons  in  place  of  the  $10  assumed 
as  the  ordinary  present  cost,  works  could  be  designed 
which  would  remove  the  bacteria  and  other  impurities 
far  more  completely  than  any  works  now  in  service  are 
able  to  do.  Even  now  financial  conditions  would  often 
justify  larger  expenditures  for  water  purification  than 
are  actually  made  if  adequate  results  could  not  be  other- 
wise obtained,  and  the  instances  where  this  is  the  case 
are  sure  to  increase  rapidly  as  the  years  go  by. 


[Hydraulic  Washing  of  Dirty  Sand  from  Sand  Filters,  Washing- 
ton, D.  C. 

(Original  design.) 


Sand  Washer  and  Sand  Bins,  Washington  Filters. 
(Improved  design.) 


HYGIENIC  STANDARDS  OF  PURIFICATION.        13! 

It  may,  therefore,  be  reasonably  anticipated  that  still 
more  efficient  methods  of  purification  will  come  to  be 
used  in  course  of  time,  and  in  discussing  the  advantages 
and  disadvantages  of  the  use  of  river  and  other  polluted 
waters  after  purification  by  cities  through  a  long  term 
of  years  with  steadily  increasing  amounts  of  pollution, 
it  will  not  do  to  consider  only  the  methods  of  purification 
now  in  use.  Better  methods  will  be  available  for  the 
more  difficult  service  when  they  are  needed. 


CHAPTER  XII. 
STORAGE  OF  FILTERED  WATER 

FILTERED  water  is  in  general  to  be  stored  only  in  cov- 
ered reservoirs  where  it  is  not  exposed  to  strong  light 
Ground  water,  which  is  water  that  has  been  filtered  by 
nature  in  passing  through  the  soil,  is  to  be  treated  in  the 
same  way. 

There  are  many  cases  where  such  waters  are  stored  in 
open  reservoirs;  in  these  cases  the  waters  always  deteri- 
orate in  quality,  but  not  always  to  the  extent  of  making 
them  inacceptable. 

Deterioration  takes  place  principally  in  warm  weather. 
It  results  from  the  growth  of  microscopic  organisms  in 
the  water.  The  mineral  food  supply  (corresponding  to 
fertilizer  on  a  wheat  crop)  is  always  contained  in  the 
water  and  in  the  air.  The  organisms  decompose  car- 
bonic acid  always  present  in  both  air  and  water,  with  the 
aid  of  the  light,  and  build  up  from  the  carbon  obtained 
from  it  the  organic  matters  of  which  they  are  composed, 
precisely  as  the  wheat  plant  builds  up  its  structure  from 
inert  mineral  matters.  If  time  and  other  conditions  per- 
mit, the  organisms  will  grow  until  the  water  becomes 
offensive  with  them,  and  the  products  of  their  growth 
and  decay. 

Filtered  waters  are  stored  in  open  reservoirs,  i.e.,  in 
old  reservoirs  previously  used  for  raw  water,  at  Lawrence, 

132 


RESERVOIRS  FOR  FILTERED  WATER.          133 

\lbany,  Washington,  Watertown,  Paterson,  Hackensack, 
and  many  smaller  places.  In  some  cases  not  much  trou- 
ble has  been  experienced;  in  others,  the  conditions  have 
been  far  from  satisfactory. 

Practically  all  reservoirs  built  for  filtered  water  in  the 
last  years  have  been  covered,  and  some  old  open  reser- 
voirs have  been  covered.  This  has  happened  more  fre- 
quently in  the  case  of  ground  water  supplies  than  in  the 
case  of  filtered  water  supplies. 

The  advantage  of  storing  filtered  waters  in  the  dark, 
where  they  will  keep  entirely  without  deterioration,  is  so 
great  that  it  seems  certain  that  the  present  practice  of 
covering  will  be  continued  until  the  present  open  reser- 
voirs are  all  abandoned  or  covered. 

Covered  reservoirs  for  filtered  water  have  been  built 
at  many  places.  Among  them,  at  Albany,  Watertown, 
Ithaca,  Yonkers,  N.  Y.,  Washington,  D.  C.,  Philadel- 
phia, Pa.,  and  by  the  East  Jersey,  Hackensack,  Queens 
County  and  Superior  Water  Companies.  It  should  be 
noted  that  in  many  cases  there  are  several  reservoirs, 
some  open  and  some  covered  in  the  same  city. 


CHAPTER  XIII. 

ON    THE    REQUIRED    SIZES    OF    FILTERS    AND 
OTHER    PARTS    OF    WATER   WORKS. 

ONE  of  the  most  perplexing  questions  to  a  beginner  is 
to  find  the  reasons  for  the  apparent  discrepancies  in  the 
sizes  of  the  different  parts  of  a  well  designed  water  works 
system.  If  a  system  is  capable  of  supplying  15,000,000 
gallons  per  day,  it  would  seem  at  first  thought  that  all 
parts  should  be  of  this  capacity  and  that  nothing  beyond 
it  would  be  necessary.  But  this  condition  is  never  real- 
ized. The  pumps  have  one  capacity,  the  pipes  another, 
the  filters  still  another,  and  the  plant  is  declared  to  be  too 
small  while  the  average  consumption  of  water  is  below 
any  of  the  figures  given  for  the  capacities  of  the  com- 
ponent parts,  f 

In  laying  out  a  system  of  works  there  is  no  matter 
which  calls  for  more  careful  study  than  the  most  advan- 
tageous sizes  of  these  component  parts.  To  some  extent 
these  sizes  are  not  capable  of  calculation,  but  are  matters 
of  judgment.  The  judgment  to  be  valuable  must  be 
based  on  extended  experience,  and  must  take  into  ac- 
count all  the  particular  conditions  in  the  case  in  hand. 

Let  us  take  a  particular  case  to  illustrate  in  a  general 
way  the  method  of  getting  at  these  sizes. 

The  city  under  consideration  has  a  present  population 
of  80,000,  we  will  say.  The  works  now  built  should  be 

134 


AMOUNTS  OF  WATER  PER  CAPITA.  135 

large  enough  so  that  no  addition  will  be  required  for  ten 
years.  In  some  parts  it  may  be  worth  while  to  anticipate 
growths  for  a  longer  period.  The  rate  of  growth  to  be 
anticipated  is  judged  from  the  past  rate  of  this  particular 
city,  and  of  other  cities  similarly  situated,  taking  also  into 
account  any  special  conditions  likely  to  make  it  grow 
either  more  or  less  rapidly  than  it  has  done,  or  than  its 
neighbors.  In  this  case  we  will  say  that,  all  things  con- 
sidered, 25  per  cent  per  decade  seems  a  reasonable  al- 
lowance. Adding  25  per  cent  to  the  present  population 
brings  us  to  a  population  of  100,000,  which  must  be 
provided  for  in  the  first  construction. 

The  amount  of  water  per  capita  is  next  to  be  con- 
sidered. This  depends  somewhat  upon  the  habits  of 
the  people  as  to  the  use  of  water  for  domestic  purposes, 
and  for  watering  lawns  and  streets;  somewhat  upon  the 
amount  of  water  sold  now  or  likely  to  be  sold  for  manu- 
facturing, railway,  and  trade  purposes;  and  still  more 
upon  the  amount  of  water  that  is  wasted  by  takers  and 
the  amount  lost  by  leakage  from  the  pipes. 

The  present  consumption  we  will  say  is  100  gallons 
per  capita  daily.  A  greater  manufacturing  use  is  to  be 
anticipated,  but  on  the  other  hand,  it  is  proposed  to  in- 
stall more  meters  upon  the  services  which  will  reduce 
the  waste.  This  will  offset  the  increase  in  actual  use  per 
capita,  and  we  will  consider  100  gallons  per  capita  daily 
as  the  probable  consumption  ten  years  hence. 

The  quantity  of  water  to  be  provided  is  thus  100  gallons 
per  capita  for  a  population  of  100,000,  or  10,000,000 
gallons  per  day. 

Ten  million  gallons   per  day  is   the   average  daily 


136  REQUIRED   SIZES   OF  FILTERS,   ETC. 

amount  for  the  year.  Sometimes  the  use  will  be  less 
and  sometimes  more  than  the  average.  There  are  few 
cities  where  the  maximum  month  does  not  exceed  the 
annual  average  by  15  per  cent.  There  are  some  where 
it  is  50  per  cent  greater.  In  this  case  25  per  cent  is 
assumed. 

The  maximum  monthly  consumption  will  thus  be  25 
per  cent  above  the  average,  or  12,500,000  gallons  per 
day. 

The  maximum  daily  consumption  must  be  taken  as 
10  per  cent  more  than  this  figure,  or  13,750,000  gallons 
per  day. 

During  some  hours  of  the  day  the  rate  of  consump 
tion  is  far  greater  than  at  other  hours.  The  excess  of 
the  maximum  hourly  rate  over  the  average  daily  rate  is 
more  nearly  in  proportion  to  the  population  supplied 
than  it  is  to  the  average  amount  of  supply.  Tn  other 
words,  the  use  of  water  fluctuates,  while  the  waste  does 
not  fluctuate,  and  where  waste  is  large  in  proportion  the 
fluctuations  expressed  in  percentage  of  the  whole  are 
less.  In  this  case  a  rate  of  80  gallons  per  capita  is  taken 
as  representing  the  excess  of  maximum  rate  of  consump- 
tion over  the  average  of  100.  The  maximum  rate  of 
use,  therefore,  will  be  at  the  rate  of  180  gallons  per  capita, 
or  18,000,000  gallons  per  day. 

This  does  not  include  the  water  required  for  fire  ser- 
vice, which  must  still  be  added.  For  ordinary  fires 
which  are  quickly  put  out,  no  very  heavy  drafts  are 
made.  But  for  the  larger  fires,  which  occur  at  long 
intervals,  a  liberal  supply  must  be  furnished. 

In  this  case,  taking  into  account  the  nature  of  the  sit- 


MAXIMUM    RATES    OF    DRAFT.  137 

uation  and  value  of  the  property,  we  assume  that  water 
to  supply  30  standard  fire  streams  should  be  available. 
Such  streams  use  250  gallons  of  water  per  minute,  or  at 
the  rate  of  360,000  gallons  per  day  for  each  fire  stream. 
Thirty  streams  will  require  water  at  the  rate  of  10,800,000 
gallons  per  day. 

If  this  was  added  to  the  maximum  rate  of  use,  18,000,000 
gallons  per  day,  it  would  give  the  extreme  maximum  rate 
to  be  provided  for  of  28,800,000  gallons  per  day. 

Actually  there  is  so  little  probability  of  the  occurrence 
of  the  maximum  fire  at  precisely  the  time  of  the  maxi- 
mum use  of  water  for  other  purposes  that  we  can  afford 
to  take  a  few  chances  on  it,  and  this  figure  may  be  cut 
somewhat.  With  an  average  use  of  100  gallons  per 
capita,  rates  exceeding  130  gallons  per  capita  would  not 
occur  for  more  than  a  small  percentage  of  the  time. 
This  would  be  13,000,000  gallons  per  day.  Adding  our 
30  fire  streams,  or  10,800,000  gallons  per  day,  to  this, 
we  have  23,800,000,  or  say  25,000,000  gallons  per  day, 
as  the  amount  which  the  works  must  be  capable  of  sup- 
plying when  there  is  demand  for'it  in  case  of  a  heavy  fire. 

It  is  only  necessary  to  prepare  to  supply  water  at  this 
highest  rate  for  three  or  four  hours,  but  the  works  must 
be  able  to  supply  water  at  the  maximum  daily  rate  of 
13,750,000,  or  say  14,000,000  gallons  per  day,  when 
required,  for  a  number  of  days  in  succession. 

We  can  now  take  up  the  sizes  required  for  the  different 
parts  of  the  works. 

If  an  impounding  reservoir  and  its  catchment  area 
are  sufficient  to  maintain  a  constant  supply  in  a  dry 
year  equal  to  the  annual  average  contemplated  use,  that 


138  REQUIRED  SIZES  OF  FILTERS,  ETC. 

will  suffice.  The  reservoir  will  take  care  of  fluctuations 
in  the  rate  of  draft,  and  no  computation  need  be  made 
of  the  effect  of  such  fluctuations. 

The  pipe  line  leading  from  the  impounding  reservoir 
to  the  distributing  reservoir  near  the  city  must  have  a 
capacity  equal  to  the  maximum  daily  use  of  14,000,000 
gallons  per  day,  or  40  per  cent  above  the  average  annual 
use 

The  hourly  fluctuations  will  be  balanced  by  the  dis- 
tributing reservoir.  The  storage  capacity  required  to 
balance  the  fluctuations  of  ordinary  use  will  be  about 
15  per  cent  of  the  average  daily  use  or  1,500,000  gallons. 
In  addition  to  this,  enough  capacity  to  maintain  the 
maximum  fire  draft  for  four  hours  should  be  added.  This 
will  require: 

~  (25  —  10)  =2, 500,000  gallons  capacity. 

This  makes  the  required  capacity  of  the  distributing 
reservoir  4,000,000  gallons  per  day. 

It  is  not  usually  convenient  to  so  operate  a  plant  as  to 
keep  the  distributing  reservoir  always  full,  and  a  fire 
might  occur  when  it  was  somewhat  drawn  down.  To 
provide  for  this  a  further  allowance  should  be  made, 
bringing  the  capacity  to  5,000,000  gallons,  or  one-half  a 
day's  average  supply.  And  if  the  fire  risk  is  large,  the 
site  suitable,  and  the  financial  conditions  warrant  it,  a 
larger  reservoir,  up  to  at  least  a  full  day's  supply,  will  be 
safer  and  better. 

Purification  works  and  pumps,  if  used,  located  between 
the  impounding  reservoir  and  the  distributing  reservoir, 
must  have  capacities  equal  to  the  maximum  day's  use, 


SIZE  OF  DISTRIBUTING  RESERVOIR.  139 

and,  in  addition,  reserve  units  or  capacity  must  be  pro- 
vided to  cover  the  time  lost  in  cleaning  niters  and  in  re- 
pairing pumps;  and  it  is  customary  to  have  a  reserve  unit 
of  each  kind,  so  that  the  supply  would  not  be  crippled 
by  having  one  pumping  or  filtering  unit  out  of  service 
for  some  time. 

As  a  general  rule,  where  the  distributing  reservoir 
balances  hourly  fluctuations  and  provides  for  fire  service 
requirements,  the  filters  should  have  a  capacity  a  half 
greater  than  the  average  rate  of  consumption,  and  the 
pumps  should  have  a  nominal  capacity  twice  as  great  as 
the  average  rate  of  pumping. 

The  average  rate  of  the  filters  will  thus  be  two-thirds 
of  the  maximum  rate,  and  the  pumping  machinery  will 
operate  equal  to  one-half  its  nominal  capacity  when  the 
capacity  of  the  plant  is  reached.  At  all  other  times  the 
ratio  of  use  to  capacity  will  be  less. 

The  pipes  from  the  distributing  reservoir  to  the  city, 
and  through  it,  must  have  a  capacity  up  to  the  maximum 
rate  of  use  of  25,000,000  gallons  per  day. 

If  the  water  is  pumped  from  the  reservoir  to  the  city, 
the  pumps  must  have  this  capacity  with  one  unit  in 
reserve.  This  means  practically  that  the  pumps  for 
direct  service  must  have  a  capacity  equal  to  three  times 
the  average  rate  of  use.  In  small  works  the  pumps 
must  be  even  larger  than  this  in  proportion. 

It  never  pays  to  build  filters  and  purification  works  to 
meet  the  maximum  rate  of  consumption.  Even  in  case 
of  a  river  supply  and  direct  pumping  of  the  filtered  water 
into  the  distribution  pipes,  it  pays  to  provide  a  pure  water 
reservoir  at  the  filters  to  balance  the  hourly  fluctuations 


140  REQUIRED  SIZES  OF  FILTERS,  ETC 

in  rate.  This  permits  the  purification  plant  to  work  at 
a  constant  or  nearly  constant  rate  throughout  the  twenty- 
four  hours,  which  is  advantageous. 

The  figures  used  in  this  illustration  are  representative, 
but  there  are  reasons  in  particular  cases  why  higher  or 
lower  values  must  be  used.  But  in  every  case  there  are 
certain  ratios  that  must  be  met.  With  pumps  capable 
of  lifting  10,000,000  gallons  per  day,  and  filters  capable 
of  filtering,  and  pipes  capable  of  carrying  this  quantity, 
it  has  never  been  possible,  and  it  never  will  be  possible, 
to  deliver  under  the  required  conditions  of  practical  ser- 
vice 10,000,000  gallons  of  water  per  day,  nor  even  an 
approximation  to  this  amount. 

This  matter,  although  very  simple,  is  mentioned  at 
length  because  it  is  one  of  the  most  common  matters  to 
be  misunderstood,  and  a  perfectly  clear  understanding 
of  it  is  essential. 

Some  most  important  projects  have  been  seriously 
defective  and  incapable  of  their  supposed  capacities  be- 
cause of  inadequate  allowances  of  this  kind. 


CHAPTER  XIV. 

AS    TO    THE    PRESSURE    UNDER    WHICH   WATER    IS 
TO    BE    DELIVERED. 

IN  considering  source  of  supply,  the  question  of  the 
elevation  of  the  source  and  of  the  distributing  reservoir 
is  often  an  important  matter,  as  it  concerns  the  pressure 
under  which  water  is  or  might  be  supplied. 

In  the  older  American  water  works  only  very  moderate 
pressures  were  used.  In  New  York,  Boston,  Philadel- 
phia, Washington,  and  a  hundred  other  cities  the  works 
were  laid  out  so  that  with  reasonably  satisfactory  piping, 
water  was  available  in  the  highest  stories  of  the  houses 
that  were  common  at  that  time,  or,  in  a  general  way,  in 
houses  three  or  four  stories  high.  The  works  were  fur- 
ther generally  arranged  to  maintain  this  pressure  only 
in  those  parts  of  the  cities  which  wrere  comparatively  low 
in  elevation,  those  parts  at  the  time  having  contained 
most  or  all  of  the  houses  for  which  public  supply  was 
regarded  as  necessary. 

The  elevation  of  the  reservoir  once  fixed  for  a  certain 
service  and  pressure,  it  is  by  no  means  an  easy  matter 
to  change  it,  and  the  elevation  and  pressure  thus  estab- 
lished many  years  ago  have  been  in  most  cases  main- 
tained to  the  present  day,  even  though  the  conditions 
have  so  far  changed  that  if  new  works  were  now  being 
laid  out,  the  arrangements  made  would  certainly  be  very 
different  from  the  actual  ones. 

141 


142  WATER  PRESSURE. 

Occasionally  where  new  or  additional  works  are  laid 
out,  there  is  an  opportunity  to  change  the  conditions 
in  this  respect.  Such  change  nearly  always  involves 
the  abandonment  of  some  old  structures,  especially 
reservoirs  that  are  too  low  for  the  new  conditions; 
and  sometimes  old  pipes  not  strong  enough  to  stand 
the  new  pressure.  Changes  in  pumping  stations 
may  also  be  involved,  or  the  construction  of  new 
ones. 

The  reasons  for  and  against  such  changes  must  be 
carefully  weighed.  But  in  many  cases  the  old  condi- 
tions are  so  thoroughly  inadequate,  that  radical  and 
expensive  changes  are  desirable  and  necessary. 

The  tendency  of  the  times  is  clearly  to  the  use  of  much 
higher  pressures. 

Higher  pressures  are  desirable  for  a  number  of  rea- 
sons, among  them  the  following: 

(i)  Buildings  are  in  general  much  higher  than  a 
generation  ago.  Practically  all  of  the  higher  buildings 
in  the  above  mentioned  cities,  and  in  many  others,  find 
it  necessary  to  install  pumps  to  lift  the  water  to  tanks  on 
their  roofs,  from  which  the  supply  in  the  building  is 
maintained.  In  New  York  City  alone  many  thousands 
of  buildings  are  obliged  to  maintain  their  own  pumping 
plants  and  tanks.  The  aggregate  cost  of  installing 
these  private  supplementary  works,  and  of  operating 
them,  is  very  large.  If  the  city  could  increase  the  water 
pressure  in  the  mains  so  as  to  make  these  private  works 
unnecessary,  this  cost  would  be  saved  to  the  citizens, 
and  the  saving  so  made  would  probably  greatly  exceed 
the  cost  of  increasing  the  pressure  of  the  public  supply, 


HIGHER  PRESSURES  NEEDED.  143 

even  though  that  involved,  as  it  would,  many  new,  exten- 
sive and  costly  works. 

(2)  Cities  in  growing  have  extended  to  higher  land 
than  that  originally  occupied,  and  for  such  higher  areas 
the  service  is  particularly  deficient.     In  many  cases  such 
higher  areas  are  left  to  get  on  as  best  they  can  with  the 
pressure  that  is  available.     When  they  are  so  high  that 
such  service  is  entirely  inadequate,  separate  high  service 
systems  have  usually  been  installed.     That  is  to  say, 
such  areas  are  supplied  by  an  entirely  separate  system 
of  pipes,  and  water  is  pumped  or  otherwise  supplied  to 
them  at  a  higher  level  or  under  greater  pressure  than  is 
used  in  the  main  service. 

Many  areas  are  so  high  above  the  lower  part  of  the 
cities  that  separate  high  service  districts  are  really  nec- 
essary, but  there  are  many  other  cases  where  the  areas 
could  be  supplied  satisfactorily  from  the  main  service  if 
the  pressures  in  the  older  and  lower  parts  of  the  cities 
were  increased  to  the  points  which  would  be  most  advan- 
tageous for  them  on  their  own  account.  In  general,  it 
is  best  to  keep  the  pipe  systems  as  simple  as  possible,  and 
to  avoid  separate  high  service  systems  where  the  service 
to  the  higher  districts  can  be  reasonably  maintained  in 
another  way. 

(3)  Higher  pressure  is  desirable  for  fire  service;  that 
is  to  say,  for  use  in  putting  out  fires.     There  are  very 
wide    differences   in    the    capacities    of  different   water 
works  systems  for  this  use.     In  European  water  works 
practice,    owing    principally    to    the    less    inflammable 
nature  of  the  buildings,  but  little  provision  is  made  for 
fire  service.     The  water  pipes  are  provided  to  distribute 


M4  WATER  PRESSURE. 

the  water  from  the  source  to  all  the  points  where  it  is 
taken,  and  in  the  quantities  needed  for  ordinary  require- 
ments. Some  provision  is  made  for  anticipated  growth, 
and  allowance  is  made  for  fluctuations  in  rate  occurring 
in  the  different  hours  and  minutes  of  the  day;  but  in 
general  the  pipes  are  small  in  size,  especially  the  lateral 
pipes,  which  are  often  as  small  as  four,  three,  and  even 
two  inches  and  less  in  diameter. 

Some  early  American  water  works  were  laid  on  this 
plan,  but  it  is  to  be  found  now  in  general  only  in  small 
villages  which  have  grown  very  slowly,  most  of  them 
having  spring  water  supplies.  Such  supplies  do  not 
furnish  much  fire  protection.  Buckets  of  water  may  be 
obtained  to  put  out  a  starting  fire,  but  no  effective  fire 
stream  from  a  hose  can  be  obtained  to  put  out  a  fire 
already  under  way. 

The  first  step  in  providing  fire  service  is  to  arrange 
the  pipes  so  that  a  supply  of  water  to  fire  engines  or 
pumps  can  be  obtained  from  them.  To  do  this  requires 
the  provision  of  a  reservoir  or  pumps  to  deliver  water  to 
the  pipes  at  a  greatly  increased  rate  in  case  of  fire,  and 
increasing  the  sizes  of  the  pipes  above  the  sizes  required 
for  ordinary  service  to  such  an  extent  that  the  required 
quantity  for  fighting  a  fire  in  addition  to  the  usual  flow 
can  be  taken  from  hydrants  in  any  part  of  the  city. 

This  result  is  more  easily  obtained  where  pipe  lines 
are  cross-connected  into  a  "gridiron  system,"  as  is  now 
customary.  By  this  means  every  pipe  is  reinforced 
within  a  reasonable  distance  by  a  number  of  other  pipes, 
and  the  quantity  of  water  that  can  be  drawn  from  it  is 
correspondingly  increased.  With  the  fire  engine  system 


FIRE  PROTECTION.  145 

no  effort  is  made  to  supply  water  for  fire  service  under 
pressure  sufficient  for  direct  use  without  fire  engines,  and 
there  is  therefore  no  need  of  raising  the  pressure  on  the 
whole  system  because  of  the  fire  service  to  be  obtained 
from  it,  The  pressure  required  to  throw  streams  of  water 
on  to  the  fire  is  all  obtained  from  steam  fire  engines  con- 
nected with  the  hydrant  or  hydrants  nearest  to  the  fire. 

Years  ago  four-inch  pipe  was  laid  in  water  works 
systems,  to  be  used  in  this  way;  but  this  proved  inade- 
quate in  practice,  and  the  minimum  size  now  used  is  six 
inches  in  diameter.  In  New  York  City,  the  minimum 
size  now  laid  is  eight  inches,  and  in  districts  of  large, 
inflammable  buildings  the  minimum  size  is  still  larger. 
This  arrangement,  with  modifications  here  and  there,  is 
in  use  in  Boston,  New  York,  Philadelphia,  Washington, 
and  most  of  the  older  cities  supplied  by  gravity  from 
reservoirs,  at  relatively  low  elevations. 

The  next  step  in  fire  protection  is  that  known  some- 
times as  the  Holly  system.  This  is  used  only  for  sup- 
plies which  are  pumped,  and  is  commonly  used  in  the 
smaller  cities  of  the  Middle  States.  Pumps  are  provided 
of  a  capacity  greatly  in  excess  of  the  ordinary  use,  and 
built  to  produce  a  pressure  much  beyond  that  needed  for 
ordinary  service.  Ordinarily  the  pumps  are  operated 
slowly,  and  only  a  moderate  pressure  is  maintained. 
Extra  boilers  are  kept  with  steam  up,  and  in  case  of  an 
alarm  of  fire  the  pump  is  at  once  speeded  up  to  give  an 
extra  volume  and  an  extra  pressure.  The  pressure  is 
commonly  increased  to  the  point  where  the  hose  can  be 
attached  to  hydrants  and  good  fire  streams  obtained 
directly  from  them  without  the  use  of  fire  engines  to 


146  WATER  PRESSURE. 

further  increase  the  pressure.  A  pressure  of  70  pounds 
per  square  inch  at  the  hydrant  is  regarded  as  about  the 
minimum  for  this  service,  and  to  secure  this,  even  in  per- 
fectly flat  country,  a  somewhat  greater  pressure  at  the 
pumping  station  must  be  carried  to  cover  the  loss  of  head 
by  friction  in  the  pipes.  Pressures  of  one  hundred  pounds 
and  over  are  common.  More  pressure  is  needed  if  the 
buildings  to  be  protected  are  large  and  high.  In  this 
system  the  pump  at  the  water  works  station  does  the 
work  that  would  otherwise  be  done  by  the  fire  engines. 

This  system  works  well  in  small  towns  where  fires  do 
not  occur  often.  In  large  cities,  with  frequent  fire 
alarms,  the  disturbances  from  fluctuating  pressure  would 
be  too  great,  and  the  system  is  not  used. 

At  Chicago,  Detroit,  etc.,  where  direct  pumping  and 
no  reservoirs  are  used,  the  increased  rate  of  draft  is  taken 
care  of  by  the  pumps,  but  no  effort  is  made  to  increase 
the  pressures  during  fires  so  as  to  allow  direct  fire  streams 
to  be  used.  Fire  engines  are  always  used  to  give  the 
additional  pressure  required. 

The  next  step  in  giving  more  fire  service  is  the  main- 
tenance at  all  times  of  pressure  in  the  pipes  high  enough 
for  fire  service.  When  this  is  done,  every  fire  hydrant  is 
just  as  good  as  a  fire  engine  up  to  the  capacity  of  the  pipes. 
This  system  has  been  adopted,  especially  with  gravity 
sources  of  supply  high  enough  in  elevation  to  maintain 
such  a  service  without  pumping.  Such  supplies  are  often 
in  hilly  country,  and  the  pressures  in  different  parts  of 
the  area  served  may  vary  greatly.  Full  fire  service  may 
be  maintained  on  the  lower  levels,  and  less  adequate 
service  supplemented  by  fire  engines  may  be  used  on  the 


FIRE  PROTECTION. 


147 


higher  levels.  As  the  largest  buildings  are  usually  upon 
the  lower  levels,  this  arrangement  works  very  well. 
Among  the  cities  having  such  comparatively  high  pres- 
sure are  the  following: 


Place. 

Extreme  maxi- 
mum pressure, 
pounds 

Maximum 
pressure  over 
a  considerable 
area,  pounds. 

Ordinary  mini- 
mum pressure, 
pounds. 

Fitchburg    . 

I7O 

75 

Syracuse          .       ... 

IOO 

QO 

60 

Westfield     

IK 

Springfield 

J4S 

I4O 

70 

Worcester    

I7o 

70 

Newark    „    . 

Peekskill  

158 

158 

Kingston     

140 

6c 

Fall  River  

130 

80 

Providence          . 

I2O 

114 

o"c 

There  are  some  disadvantages  of  high  pressure,  real 
and  supposed; 

Where  the  water  is  pumped,  the  cost  of  pumping  is 
increased.  This  is  a  question  of  cost,  and  the  cost  can 
be  computed. 

Increasing  the  pressure  tends  to  a  greater  waste  of 
water.  If  all  the  openings  remained  the  same,  the  water 
waste  would  increase  as  the  square  root  of  the  average 
pressure.  Multiplying  the  pressure  by  four  would  in- 
crease the  waste  by  two.  For  a  comparatively  small 
increase,  adding  two  per  cent  to  the  pressure  would  add 
one  per  cent  to  the  amount  of  waste.  Actually  the  in- 
crease of  waste  is  not  in  this  proportion,  for  leakage 
from  a  pipe  under  higher  pressure  makes  more  noise  aiA* 
is  more  easily  discovered  than  leakage  from  a  pipe  under 


148  WATER  PRESSURE. 

lower  pressure,  and  it  is  therefore  more  likely  to  be 
discovered  and  stopped. 

Formerly  there  may  have  been  difficulty  in  providing 
pipes  and  plumbing  to  stand  successfully  as  high  pres- 
sures as  may  now  be  considered.  But  there  is  no  trouble 
in  securing  pipes  and  fixtures  to  do  it  now.  An  increase 
in  pressure  may  be  somewhat  destructive  of  some  old 
plumbing,  but  pressure  reducers  can  be  put  on  to  indi- 
vidual houses  to  avoid  this  with  considerable  success; 
and  in  any  new  work  the  additional  pressure  is  not 
objectionable,  and  does  not  increase  the  cost  of  properly 
designed  plumbing.  Better  work  is  required,  but  the 
sizes  may  be  smaller. 

In  recent  years  a  great  many  cities  have  installed  spe- 
cial high  pressure  services  for  fire  use  These  are  usu- 
ally entirely  independent  of  the  ordinary  water  supply, 
and  they  are  mentioned  here  briefly  only  for  complete- 
ness. In  several  cases  salt  water  is  used  for  this  service. 
Otherwise,  river  or  lake  water  is  taken  at  the  nearest 
point,  regardless  of  quality.  Pressure  is  only  kept  up 
when  needed. 

In  other  cases  the  high  pressure  water  is  from  the  same 
source  as  the  ordinary  supply,  and  the  fire  pressure  may 
be  constantly  kept  upon  the  special  pipes  if  it  is  a  gravity 
supply.  This  last  arrangement  has  the  advantage  of 
allowing  especially  high  buildings  to  be  supplied  from 
the  high  pressure  pipes,  and  it  is  not  unusual  for  the 
same  system  of  pipes  that  supplies  extra  pressure  down- 
town to  extend  to  and  supply  at  ordinary  pressures  parts 
of  the  city  upon  higher  land.  In  other  words,  the  pipes 
from  a  high  service  district  are  simply  extended  through 


FIRE  PROTECTION.  149 

a  low  service  area  having  special  need  of  high  pressure 
water.  Newark,  Worcester,  Fitchburg,  and  other  cities 
have  this  arrangement. 

American  cities  are  built  in  a  way  to  make  them  more 
subject  to  damage  by  conflagration  than  those  of  any 
other  country.  The  abundance  of  wood  in  the  past, 
and  the  cheaper  construction  with  it  as  compared  with 
other  building  materials  have  had  much  to  do  with  this. 
There  has  also  been  far  too  little  attention  paid  to  build- 
ing in  a  way  to  make  serious  fires  impossible. 

Most  of  the  buildings  now  being  erected  are  better  in 
this  respect.  Each  modern  steel  building,  with  fire- 
proof walls  and  floors,  erected  in  place  of  an  old  building 
with  wooden  floors,  reduces  the  chance  of  conflagration. 
A  bad  fire  cannot  start  in  such  a  building;  and  if  one 
starting  outside  burns  to  it,  it  tends  to  act  as  a  barrier  to 
the  fire  and  stop  its  progress. 

With  rebuilding  going  on  at  its  present  rate,  the  fire 
conditions  in  our  cities  will  improve,  until  ultimately  the 
requirements  of  fire  service  upon  the  water  works  system 
will  be  reduced  to  an  approximation  of  what  they  now 
are  in  European  cities.  That  is  to  say,  it  will  only  be 
necessary  to  provide  pipes  for  the  distribution  of  water 
for  ordinary  purposes,  with  a  comparatively  small  addi- 
tion for  fire  requirements. 

But  that  day  is  a  long  time  in  the  future.  At  the  pres- 
ent time  we  are  using  vast  numbers  of  buildings  that  are 
anything  but  fire- proof.  These  buildings  on  the  whole 
are  good  and  useful,  and  must  continue  to  be  used  for 
many  years;  and  so  long  as  they  remain,  water  works 
systems  must  be  planned  and  built  and  used  to  protect 


150  WATER  PRESSURE. 

them.  The  property  that  may  be  lost  in  a  day  through 
failure  of  water  in  a  San  Francisco  or  Baltimore  fire  will 
pay  for  very  generous  additions  to  the  pipes  and  pumps 
and  reservoirs  in  many  cities. 

Under  present  conditions  there  can  be  no  doubt  that 
far  better  fire  protection  would  pay  in  many  or  most 
American  cities,  and  it  is  well  worth  while  to  secure  it. 
But  the  certain  ultimate  improvement  in  building  con- 
ditions, that  is  to  say,  the  gradual  elimination  of  fire- traps 
and  the  substitution  of  buildings  that  are  fire-proof,  or 
nearly  so,  must  be  kept  in  mind  in  planning  for  works  to 
serve  for  long  periods. 


CHAPTER  XV. 

ON   THE    USE,    WASTE,   AND    MEASUREMENT    OF 
WATER. 

THE  quantities  of  water  supplied  in  a  number  of  Amer- 
ican cities  are  as  follows : 


Place. 


Year. 


Gallons 

Per  capita 

daily. 


Percentage 
of  services 
metered. 


Buffalo 1912 

Chicago 1911 

Pittsburgh 1910 

Philadelphia  * 1911 

Detroit 1910 

Washington 1912 

Boston 1912 

Cincinnati 1911 

St.  Louis.  — 1911 

Cleveland 1912 

Milwaukee 1912 

Newark 1911 

Louisville 1911 

New  York 1912 

Minneapolis 1912 

Worcester 1911 

Hartford 1911 

Providence 1911 

St.  Paul 1911 

Lowell 1912 

Lawrence , .  1911 

Fall  River 1911 


334 
235 
235 
202 
177 
175 
125 
125 
118 


107 

105 

104 

81 

68 

66 

65 
60 

50 
46 

44 


5 

4 

ii 

4 
10 

3 
35 

48 

7 
98 

99 

54 

7 

25 
59 
97 
98 
89 

53 
82 
92 
99 


152    USE,  WASTELAND   MEASUREMENT  OF  WATER. 


The  quantities  of  water  supplied  in  a  few  European 
cities  are  as  follows: 


Place. 

Year. 

u.  s. 

Gallons 
per  capita 
daily. 

Place. 

Year. 

U.  S. 
Gallons 
per  capita 
daily. 

London 

1008 

4.1 

Berlin.     .    . 

I  QOO 

22 

Liverpool.  .  .  . 
Paris  

1912 

IOOI 

44 
65 

Hamburg.  .  . 
Dresden.  .  .  . 

1910 
igOQ 

8l 
26 

Amsterdam  . 

IQOS 

37 

Copenhagen 

1909 

29 

And  in  Australia: 


U.S. 

U  S. 

Place. 

Year. 

Gallons 
per  capita 
daily. 

Place. 

Year. 

Gallons 
per  capita 
daily. 

Melbourne. 

I9°5 

63 

Brisbane 

1906 

58 

Sydney    .   . 

1905 

39 

Taking  it  right  through,  probably  one-half  the  water 
supplied  to  American  cities  is  wasted.  Some  of  this 
waste  is  unavoidable,  but  the  greater  part  of  it  could  be 
stopped. 

9  Because  of  this  great  waste  of  water  the  cost  of  the 
works  is  increased,  and  likewise  the  cost  of  maintaining 
them. 

The  increase  in  cost  is  not  as  rapid  as  the  increase  in 
quantity  of  water,  but  it  is  substantial.  Probably  the 
whole  cost  of  supplying  water  in  America  is  from  a  third 
to  a  half  greater  than  it  would  be  with  the  reasonable  sup- 
pression of  waste.  In  some  cases  the  ratio  is  much  greater. 

If  the  policy  of  Buffalo  and  Chicago  is  to  be  followed 
in  allowing  everyone  to  take  and  waste  water  as  freely 
as  he  likes  without  paying  for  it,  then  the  source  of 


GREAT  WASTE  OF  WATER.  153 

supply  and  other  parts  of  the  works  must  be  provided 
with  a  capacity  four  times  as  great  as  where  the  policy  of 
Worcester  and  Hartford,  of  making  each  one  who  draws 
water  pay  for  the  amount  drawn,  is  followed. 

The  advantages  of  putting  a  meter  on  each  service  and 
collecting  water  rates  according  to  its  indication  are  so 
great  and  so  obvious  to  all  who  have  studied  the  water 
question,  that  this  system  promises  to  become  universal 
in  America  at  no  remote  date. 

When  this  happens  such  preposterous  conditions  as 
securing  and  pumping  at  great  expense  250  gallons  for 
each  man,  woman,  and  child  of  the  population,  of  which 
amount  four-fifths,  more  or  less,  is  lost  by  leakage  ab- 
solutely without  benefit  to  anyone,  will  cease  to  exist. 
'  On  the  other  hand,  it  must  not  be  forgotten  that  in 
America  water  is  a  relatively  cheap  commodity,  and  it  is 
likely  to  remain  so,  and  people  will  not  limit  themselves 
closely  in  its  use.  Wealth  is  increasing;  we  live  in  larger 
houses,  have  more  bath  tubs  and  other  fixtures  and 
use  them  oftener;  generous  lawns  and  wide  streets  need 
water  to  keep  them  presentable,  and  at  fair  prices  it  can 
be  easily  afforded. 

Let  our  aim  be  a  generous  use  of  water,  but  no  waste, 
and  each  man  to  pay  for  what  he  gets. 

It  is  idle  to  attempt  to  ascertain  what  the  per  capita 
consumption  for  any  city  in  the  future  will  be.  To  fore- 
cast it  roughly  for  a  few  years  is  all  that  need  be  done  or 
can  be  done.  The  water  resources  of  the  country  are 
enormous,  and  they  must  be  developed  gradually  as  there 
is  need  of  them,  and  it  is  the  clear  duty  of  the  water 
departments  and  water  companies  to  develop  them  as 
they  are  needed. 


154      USE,  WASTE,  AND  MEASUREMENT  OF  WATER. 

In  some  cases  where  unrestricted  waste  has  been  per- 
mitted, large  reductions  are  possible  by  changing  the 
methods  of  sale;  but  in  many  other  cases  there  will  be 
increases  as  people  use  more  water  and  are  willing  to 
pay  for  it.  It  is  clear  that  per  capita  consumptions  as 
low  as  those  in  some  European  cities  are  not  to  be  antici- 
pated or  desired  in  America.  The  tendency  is  the  other 
way.  The  European  figures  are  steadily  increasing,  even 
where  all  water  is  sold  by  meter. 

Meter  Rates  and  the  Sale  of  Water.  Much  of  the  un- 
fortunate and  ignorant  opposition  to  the  use  of  meters 
has  been  caused  by  unreasonable  and  unjust  methods  of 
charging  for  the  water  passing  the  meters.  There  has 
been  the  greatest  diversity  in  these  methods  of  charging, 
but  the  underlying  principles  that  should  govern  are 
being  slowly  worked  out,  and  improvements  in  schedules 
of  charges  for  metered  water  are  slowly  but  surely  being 
made  by  the  water  departments  of  the  country. 

The  price  at  which  any  commodity  is  sold  will  nor- 
mally be  found  between  two  limits.  It  will  not  be  less 
than  the  cost  to  the  seller  to  produce  and  deliver,  nor  will 
it  be  greater  than  the  value  or  utility  of  the  product  to 
the  buyer.  Water  is  a  commodity  and  its  price  is  gov- 
erned by  these  limits.  When  the  works  are  owned  by  a 
city  there  is  a  strong  tendency  to  ignore  the  second  limit 
and  to  reduce  the  price  to  the  first  limit,  or  in  other  words 
to  sell  the  water  at  cost. 

In  general,  this  tendency  will  control,  but  it  does  not 
seem  necessary  that  it  should  do  so  to  the  exclusion  of 
other  considerations  in  all  cases.  One  man  gets  more 
comfort  or  makes  more  profit  from  a  thousand  gallons 


METER  RATES  AND  THE  SALE  OF  WATER.   155 

of  water  than  his  neighbor.  If  the  difference  can  be 
ascertained  and  measured,  there  would  seem  to  be  no 
reason  why  it  should  not  be  taken  into  account  in  fixing 
the  rates.  Of  course,  the  practical  difficulty  is  in  ascer- 
taining such  differences,  and  this  difficulty  will  greatly 
limit  the  use  that  can  be  made  of  the  relative  value  of 
the  service  to  the  taker,  but  in  some  cases  use  may  be 
made'of  it. 

It  may  be  noted  that  manufacturers  and  railroads  are 
not  slow  in  representing  to  water  departments  that  their 
business  will  not  stand  existing  rates,  or  that  other  sup- 
plies can  be  more  cheaply  obtained,  and,  on  such  grounds 
asking  for  reductions  in  charges.  And  these  reductions 
are  frequently  made  usually  because  the  business  is 
needed,  and  is  acceptable  to  the  water  department  even 
at  a  reduced  rate.  On  the  other  hand  if  a  water  depart- 
ment renders  a  service  which  is  especially  and  unusually 
advantageous  to  someone,  as  often  happens,  there  would 
seem  to  be  no  reason  why  a  charge  should  not  be  made 
greater  than  where  only  the  usual  benefits  result  from 
the  service. 

This  matter  aside,  the  problem  presented  is  briefly 
this :  a  certain  quantity  of  water  is  dispensed  for  all  sorts 
of  purposes,  and  a  certain  sum  of  money  is  to  be  raised 
to  meet  the  needs  of  the  department.  How  can  the 
takers  be  most  fairly  taxed  to  produce  the  required 
revenue  or  a  reasonable  approximation  thereto? 

In  the  first  place,  the  amount  to  be  raised  is  to  be 
divided  into  two  parts,  namely,  a  first  part,  including  all 
expenses  and  capital  charges,  the  amounts  of  which  are 
dependent  upon  the  amount  of  water  supplied;  and  a 


156      USE,  WASTE,  AND  MEASUREMENT  OF  WATER. 

second  part,  including  all  other  charges  and  expenses, 
which  are  those  not  dependent  upon  the  amount  of  water 
supplied. 

This  division  can  be  made  only  approximately.  Mak- 
ing it  is  a  question  for  the  accountants,  and  the  different 
items  in  the  total  schedule  of  payments  made  in  a  year 
must  be  carefully  looked  over  to  see  how  far  each  would 
be  affected  by  a  change  in  the  quantity  of  water  supplied. 
There  will  be  plenty  of  room  for  discussion  as  to  many 
of  the  items,  and  only  a  rough  approximation  need  be 
attempted.  It  may  even  be  made  arbitrarily  by  assum- 
ing that  one-half  or  one- third  of  the  total  expense  is  not 
affected  by  the  quantity  of  water  supplied. 

Having  separated  our  schedule  into  these  two  parts 
the  first  part  is  to  be  taxed  upon  the  water  according  to 
volume;  the  second  part  is  to  be  taxed  upon  the  fixtures 
and  property  according  to  rules  to  be  adopted. 

If  all  the  water  went  through  meters,  and  if  the  meters 
recorded  it  all,  the  first  sum  divided  by  the  quantity  of 
water  supplied  in  a  year  would  be  the  rate  that  would 
have  to  be  charged  for  all  water  to  produce  the  required 
revenue ;  and  there  would  seem  to  be  no  adequate  reason 
for,  nor  justification  of,  a  sliding  scale  as  it  is  called,  that 
is,  of  a  schedule  by  which  small  takers  pay  more  in 
proportion  than  large  ones. 

The  calculation  has  sometimes  been  made  in  this  way, 
when  only  a  part  of  the  water  has  been  metered,  but  it 
will  not  work  out  with  all  the  water  metered,  and  for  this 
reason  it  is  unjust  when  only  a  part  of  it  is  metered. 
There  are  two  reasons  for  this:  first,  some  water  is  lost 
by  leakage  from  the  pipes  before  the  meters  are  reached 


COMPUTATION  OF  METER  RATES,  157 

and  never  passes  through  them;  and  second,  the  meters 
practically  always  pass  more  water  thai;  they  record. 

When  water  passes  a  meter  rapidly  it  is  recorded  with 
considerable  accuracy,  but  when  it  flows  through  slowly 
some  of  it  leaks  around  the  moving  parts,  and  the  amount 
registered  is  below  the  truth.  This  is  especially  the  case 
with  meters  that  have  been  worn  by  use,  and  the  meters 
of  a  city,  as  a  whole,  register  a  smaller  proportion  of  water 
passing  them  than  is  shown  by  the  usual  shop  tests  of 
meters  even  when  these  tests  are  made  at  low  rates  of  flow. 

Meters  wear  less  rapidly  when  the  water  is  perfectly 
clear  filtered  water  or  ground  water  than  where  river  and 
other  surface  supplies  are  used. 

.  Under  present  American  conditions  it  does  not  seem 
possible  to  make  the  meters  account  for  more  than  from 
50  to  70  per  cent  of  the  supply.  This  shortage  does  not 
all  come  from  the  slip  of  the  meters.  Some  of  it  is  from 
the  leakage  from  pipes. 

There  is  reason  to  believe  that  the  proportion  of  water 
accounted  for  will  be  gradually  increased  with  better 
conditions.  Some  German  cities  do  much  better  than 
this  in  accounting  for  their  water  at  the  present  time. 

If  the  amount  that  can  be  accounted  for  is  not  known 
by  actual  experience  for  the  works  in  question,  then  the 
calculations  should  be  made  on  the  basis  that  60  per  cent 
of  the  water,  or  thereabouts,  will  be  actually  charged  for, 
and  that  this  amount  will  produce  the  full  sum  to  be 
raised  in  this  way. 

The  assessment  of  the  second  part  of  the  amount  to  be 
raised,  that  is  to  say,  the  part  that  is  not  affected  by  the 
amount  of  water  that  is  used,  presents  greater  difficulties. 


158      USE,  WASTE,  AND  MEASUREMENT  OF  WATER. 

In  studying  this  division  two  thoughts  should  be  kept 
in  mind.  First,  the  amount  charged  in  this  way  on  each 
service  should  not  be  less  than  the  sum  that  will  serve  to 
maintain  the  service  and  the  meter  upon  it  and  pay  the 
cost  of  reading  the  meter  and  of  the  proper  proportion  of 
the  bookkeeping  and  general  expenses  which  are  in  no 
way  affected  by  the  amount  of  water  that  is  used. 
Second,  the  amount  to  be  raised  in  this  way  may,  with 
propriety,  be  charged  to  some  extent,  according  to  the 
value  of  the  service  to  the  taker,  as  far  as  that  can  be  deter- 
mined by  a  simple  and  sure  method  of  calculation.  All 
property  is  more  valuable  because  a  good  water  service  is 
available  and  quite  apart  from  the  amount  of  water  that 
is  used,  and  there  is  no  reason  why  some  payment  should 
not  be  made  to  the  water  department  because  of  this 
element  of  value  in  the  service. 

The  simplest  way  of  apportioning  the  sum  to  be  raised 
in  this  way  is  to  divide  it  equally  among  the  services. 
Berlin,  Germany,  collects  twelve  marks,  equal  to  about 
three  dollars  per  annum,  for  each  service,  and  in  addition 
collects  payment  for  all  water  recorded  by  the  meters. 
Milwaukee  has  similarly  collected  one  dollar  per  annum 
for  each  service,  but  this  is  clearly  too  low  a  figure.  It 
will  not  pay  for  the  maintenance  of  the  services  and 
meters. 

A  better  way  is  to  base  the  payments  upon  the  size  of 
the  service.  Most  of  the  services  of  a  system  are  domes- 
tic services,  that  is  to  say  they  serve  residences.  These 
services  are  commonly  five- eighths  of  an  inch  in  diameter. 
The  assessment  on  these  may  be  placed  at  $3.00  per 
annum,  let  us  say.  Some  takers  insist  on  a  larger  ser- 


CHARGE  FOR  SERVICES.  159 

vice  because  they  wish  to  draw  water  more  rapidly. 
Many  discussions  take  place  because  the  prospective  taker 
is  insistent  on  a  larger  service,  while  the  water  works 
superintendent  believes  the  usual  size  to  be  sufficient. 
Why  not  let  the  taker  have  a  service  as  large  as  he  likes 
and  charge  him  for  it  in  proportion  to  its  size,  or,  let 
us  say,  approximately  in  proportion  to  its  ability  to 
deliver  water? 

Starting  with  a  charge  of  $3.00  for  a  five-eighth  inch 
service,  and  using  round  figures,  the  charge  for  larger 
services,  not  including  the  charge  for  water  would  be 

For  f-inch  .    .   « $5.00     per  annum 

For  i-inch 10.00 

For  i|-inch 20.00 

For  2-inch 30.00 

For  3-inch 70.00 

For  4-inch 125.00      " 

For  6-inch 300.00 

For  8-inch 500.00      "        " 

This  arrangement  has  the  practical  advantage  of 
making  a  substantial  charge  for  a  substantial  service, 
and  for  a  service  that  too  often  is  not  adequately  paid  for, 
where  large  pipes  lead  from  the  mains  into  mills,  ware- 
houses, etc.,  for  fire  purposes  only,  and  from  which 
pipes  ordinarily  no  water  is  drawn. 

These  pipes  cause  more  trouble  to  water  departments, 
and  the  privileges  granted  are  subject  to  more  gross 
abuse,  than  those  from  any  other  class  of  service;  and  it 
is  right  and  proper  that  substantial  payments  should  be 
made  for  them. 

Such  large  fire  services  should  always  be  metered 
and  they  should  not  be  allowed  to  exist  on  any  other  con- 
dition. This  has  not  been  possible  until  recently,  but 


160      USE,  WASTE,  AND  MEASUREMENT  OF  WATER. 

it  can  be  done  now,  for  a  type  of  meter  has  been  invented 
which  is  satisfactory  from  a  water  works  standpoint,  and 
which  does  not  interfere  materially  with  the  value  of  the 
pipe  for  fire  service.  With  this  meter  the  water  ordi- 
narily passes  through  a  by-pass  on  which  there  is  a  small 
meter.  But  in  case  of  need,  that  is  in  case  of  fire,  a  valve 
on  the  main  line  opens  automatically  and  the  full  quan- 
tity of  water  that  the  pipe  will  carry  flows  through  it 
unobstructed  for  use.  Even  in  this  case  an  approximate 
idea  of  the  amount  of  water  drawn  is  registered  by  some 
extremely  ingenious  devices  which  are  only  brought 
into  play  when  the  main  valve  is  opened. 

The  general  idea  of  charging  in  proportion  to  the 
areas  of  the  service  pipes  has  been  expressed  in  the  form 
of  minimum  rates  at  Cleveland  and  other  places.  I  do 
not  know  that  it  has  been  followed  anywhere  to  its  logical 
conclusion,  as  above  outlined. 

Another  way  to  divide  the  sum  to  be  taxed  on  ser- 
vices is  in  proportion  to  fixture  rates.  This  method  is 
applicable  especially  in  cities  which  are  gradually  chang- 
ing from  fixture  charges  to  the  meter  system.  In  this 
case  the  fixture  rates  are  known  for  each  house.  Sup- 
posing it  is  decided  to  assess  one-third  of  the  whole 
amount  to  be  raised  upon  fixtures  then  when  a  meter 
was  installed  on  a  given  service  the  charge  for  that  ser- 
vice would  be  one-third  of  the  previous  fixture  rate,  and 
in  addition  all  water  used  would  be  charged  for. 

For  these  conditions  this  system  has  much  to  recom- 
mend it.  But  it  is  a  transition  system.  When  all  ser- 
vices are  metered  it  is  not  to  be  supposed  that  it  will  be 
worth  while  to  continue  making  fixture  rates.  A  more 


OTHER  CONSIDERATIONS.  161 

simple  method  of  computation  will  be  demanded  and 
should  be  used.  This  can  be  brought  about  without 
the  slightest  trouble,  and  without  any  radical  change 
when  all  services  are  metered. 

In  England  the  charge  for  water  is  commonly  based 
on  the  rental  value  of  the  property  supplied.  People 
living  in  expensive  dwellings  pay  more  for  their  water 
than  those  living  in  cheaper  ones.  It  would  not  be 
unreasonable  in  fixing  the  amounts  to  be  assessed  on 
fixtures  to  take  into  account  either  the  rental  value  or 
the  selling  value  of  the  properties;  but  this  idea  so  far  as 
I  know  has  never  found  expression  in  American  sched- 
ules. In  New  York  and  a  few  other  cities  the  width  and 
height  of  the  house  are  taken  into  account,  but  not  the 
value. 

There  is  another  point  that  might  be  taken  into  ac- 
count with  reference  to  fire  service.  Water  works  cost 
more  to  build  and  maintain  because  there  are  so  many 
inflammable  buildings  requiring  large  volumes  of  water 
instantly  available  for  their  protection  in  case  of  fire. 
Other  buildings  are  being  erected  in  rapidly  increasing 
numbers,  so  little  inflammable  that  only  small  volumes  of 
water  are  needed  for  their  protection.  Why  should  fire- 
proof buildings  pay  as  much  as  fire-traps  toward  the 
excess  cost  of  the  service? 

It  might  not  be  possible  to  apply  this  to  domestic  ser- 
vices, but  it  certainly  could  be  applied  to  connections 
made  specially  for  fire  purposes.  If  the  price  computed 
in  proportion  to  areas  is  taken  as  the  standard,  and  ap- 
plicable to  slow-burning  well  protected  mill  construction, 
then  why  not  reduce  the  charge  to  one-half  for  thoroughly 


162      USE,  WASTE,  AND  MEASUREMENT  OF  WATER. 

fire-proof  buildings,  and  double  it  for  old  and  dangerous 
buildings?  Or  within  certain  limits  the  charges  might 
be  based  upon  the  fair  insurance  premiums  paid  on  fully 
insured  property. 

There  are  so  many  considerations  that  might  fairly  be 
taken  into  account  that  it  will  be  found  impossible  to 
make  a  schedule  recognizing  all  of  them  and  at  the  same 
time  sufficiently  certain  and  simple  to  be  satisfactory  in 
practice.  For  a  schedule  of  rates  must  be  easy  and  cer- 
tain in  application,  readily  understood  by  the  public  as 
well  as  by  the  registrar,  and  it  must  not  be  frequently  or 
arbitrarily  changed. 

Practically  the  best  way  to  handle  the  matter  is  to 
devise  a  schedule  based  on  calculations  of  the  general 
nature  indicated  above,  and  computed  to  yield  a  revenue 
of  10  per  cent  more  than  is  actually  required.  This 
excess  allowance  is  made  because  there  is  always  some 
uncertainty  as  to  the  effect  of  changing  rates  upon  the 
revenue  to  be  produced;  and  it  is  better  to  raise  some- 
what too  much  revenue  rather  than  to  fall  short. 

This  schedule  should  be  simple  and  certain,  and  all 
figures  should  be  expressed  in  round  numbers.  For 
instance,  if  the  calculation  came  that  way,  the  figures 
given  in  connection  with  the  different  sized  services 
might  be  used  and  in  addition  seven  cents  per  thousand 
gallons  for  all  water  used.  If  this  was  estimated  to 
yield  10  per  cent  more  revenue  than  required,  there 
would  be  a  chance  of  falling  below  expectations  by  this 
amount  without  embarrassing  the  department,  while 
under  other  conditions  the  revenue  might  exceed  that 
required  by  20  per  cent  or  more. 


THE  SLIDING  SCALE.  163 

In  the  case  of  an  excess  of  revenue  being  demonstrated, 
the  charge  for  water  could  be  reduced  to  six  cents  or  to 
five  cents  as  the  business  would  stand,  or  the  charge 
for  services  might  be  lowered.  Practical  experience 
with  the  general  method  would  be  available  to  indicate 
where  the  cuts  could  be  best  and  most  equitably 
made. 

The  use  of  a  sliding  scale,  that  is  to  say,  or  making 
lower  rates  to  large  takers,  is  firmly  fixed,  and  it  will 
be  hard  to  do  away  with  the  idea.  But  the  writer 
believes  that  such  a  scale  as  that  suggested  contains 
all  the  provisions  of  this  kind  that  are  necessary  or 
wise. 

In  the  first  place  this  kind  of  a  scale  is  in  reality  a 
sliding  one.  The  small  cottage  pays,  let  us  say,  $3  per 
year  for  the  service,  and  in  addition  uses  water  charged 
at  $0.10  per  1000  gallons,  let  us  say,  amounting  to  $3  per 
year  in  addition.  The  total  payment  is  $6  per  year  and 
the  average  cost  of  water  to  the  taker  is  $0.20  per  1000 
gallons. 

A  larger  taker  pays,  let  us  say,  $12  per  year  for  his 
service,  and  uses  at  the  same  rate  water  worth  $120  per 
annum.  The  whole  bill  is  then  $132  and  the  average 
cost  of  water  to  him  is  $0.11  per  1000  gallons,  against 
the  $0.20  paid  by  the  smaller  taker. 

The  basing  figures  of  course  are  to  be  fixed  to  meet 
local  conditions,  and  when  so  fixed  they  will  give  all  the 
slide  that  is  desirable.  There  is  no  reason  why  the  man 
in  a  cottage,  who  lets  his  plumbing  get  out  of  order  and 
wastes  an  extravagant  quantity  of  water,  should  be  asked 
to  pay  a  larger  price  per  thousand  gallons  for  the  water 


1 64      USE,  WASTE,  AND  MEASUREMENT  OF  WATER. 

wasted  by  his  neglect  than  is  paid  by  the  largest  estab- 
lishment. 

Manufacturers  are  often  supplied  by  cities  at  special 
rates  which  are  less  than  cost.  This  is  most  frequently 
done  on  special  pleas,  and  is  comparable  to  giving  exemp- 
tion from  taxation.  The  practice  is  not  a  wise  one  and 
should  not  be  encouraged. 

Low  rates  are  also  often  made  to  secure  customers  who 
would  not  otherwise  use  water  or  who  would  not  use  so 
much.  This  is  most  apt  to  be  done  in  the  early  days  of 
operation  of  a  system  when  the  capacity  of  the  works  built 
in  anticipation  of  growth  is  beyond  present  requirements. 
Hydraulic  elevators  and  motors  are  most,  common  and 
objectionable  subjects  for  such  special  rates.  As  long 
as  the  capacity  of  the  works  is  really  in  excess  of  the 
demand,  a  little  financial  help  is  received  by  the  depart- 
ment from  such  rates;  but  as  soon  as  the  capacity  of 
the  plant  is  approached  such  rates  become  a  drag  and 
a  source  of  loss.  Experience  shows  that  they  are  not, 
and  cannot  possibly  be  shut  off  promptly  when  they 
cease  to  be  profitable.  It  is,  therefore,  better  and  safer 
to  charge  the  regular  rates  for  water  used  for  these 
and  all  other  special  purposes,  and  to  take  good  care 
that  all  water  so  used  is  paid  for.  Some  revenue 
will  be  lost;  some  elevators  and  printing  presses  will 
be  driven  by  electricity  instead  of  by  water  power, 
but  electricity  is  a  better  way  of  transmitting  power 
than  water  under  pressure,  and  in  the  end  all  will  be 
better  off. 

American  cities  having  high  service  systems  make 
precisely  the  same  charges  for  water  from  them  as  for 


CHARGE  FOR  HIGH  SERVICE  WATER.          165 

water  from  the  low  service  pipes.  The  man  on  the  top 
of  a  hill  with  high  service  water  pays  no  more  than  the 
man  in  the  valley,  though  to  supply  him  costs  the  city 
usually  from  two  to  five  cents  more  per  thousand  gallons, 
and  where  the  high  service  districts  are  small  and  iso- 
lated the  extra  cost  may  greatly  exceed  these  figures. 
There  seems  to  be  no  well-founded  reason  for  this 
equality  in  charge  with  clearly  defined  difference  in 
cost  of  service. 

It  would  seem  rational  and  wise  to  charge  more  for 
high  service  water  than  for  low  service  water,  and  to 
establish  the  differential  carefully  at  so  many  cents  per 
thousand  gallons,  to  pay  as  nearly  as  it  can  be  computed 
for  the  additional  cost  of  the  high  service  water;  and  the 
differential  should  be  subject  to  revision  from  time  to 
time  as  the  conditions  of  service  change.  Usually  it 
would  be  higher  at  first,  with  few  takers,  and  less  as  the 
quantity  sold  became  greater. 

The  present  method  is  unfair  to  those  on  low  ground. 
They  pay  their  share  (usually  the  largest  share)  of  the 
excess  cost  of  supplying  water  to  those  located  on  the 
hills.  And  this  is  the  more  unfair,  as  the  hill  sites  are 
usually  more  desirable  for  residences,  and  those  who  live 
on  them  are  well  able  to  pay  the  added  cost  which  their 
service  entails  on  the  water  department. 

I  have  described  this  meter  rate  question  at  some 
length,  because  I  feel  strongly  that  present  methods  of 
charging  are  in  general  unfair  and  unreasonable,  and 
because  I  believe  that  the  adoption  of  the  general  prin- 
ciples here  outlined  will  do  a  great  deal  to  improve  the 
§ituation. 


166      USE,  WASTE,  AND  MEASUREMENT  OF  WATER. 

The  sooner  arbitrary  and  unreasonable  methods  are 
abandoned,  and  more  reasonable  methods  are  adopted, 
the  better  it  will  be  for  both  consumers  and  for  water 
departments,  and  the  easier  it  will  be  to  supply  clean 
water  and  to  make  the  financial  arrangements  for 
doing  it. 


CHAPTER  XVI. 
SOME    FINANCIAL   ASPECTS. 

IN  America  water  works  receipts  average  about  $2.50 
per  capita  for  the  population  supplied,  but  figures  rang- 
ing all  the  way  from  $2.00  to  $4.00  are  common,  and 
some  figures  are  outside  of  this  range.  These  are  for 
publicly  owned  works.  Private  companies  average  to 
make  about  the  same  collections  for  domestic  rates,  and 
in  addition  they  are  paid  for  fire  service,  so  that  their 
total  receipts  average  about  $3.00  per  capita.  Publicly 
owned  works  as  a  rule  receive  no  separate  payment  for 
fire  protection. 

There  seems  to  be  no  well  marked  tendency  to  either 
higher  or  lower  collections  per  capita  in  the  larger  cities, 
as  compared  with  the  smaller  ones.  Large  cities  usually 
have  to  go  farther  for  water.  Small  sources  near  at 
hand  are  not  available  to  them,  and  it  would  seem  rea- 
sonable to  suppose  that  the  relative  cost  would  be  greater. 
But  it  seems  that  the  savings  which  are  made  by  operat- 
ing on  a  larger  scale  offset  this  tendency,  and  on  the 
whole,  the  expense  of  securing  water  is  just  about  the 
same  on  an  average  in  proportion  to  population  in  small 
cities  and  in  large  ones. 

In  Europe  the  per  capita  cost  of  water  is  rather  less. 
In  London  where  the  works  of  eight  private  companies 
were  turned  over  to  public  ownership  in  1903,  and  where 

167 


1 68  SOME  FINANCIAL  ASPECTS. 

the  rates  charged  by  the  companies  continue  practi- 
cally without  change,  the  collections  amount  to  $2.00  per 
capita,  which  does  not  include  any  separate  payment  for 
fire  service. 

Paris  collects  about  $1.50  per  capita,  and  this  seems  to 
be  also  about  the  average  amount  collected  in  English 
cities,  excluding  London,  under  public  ownership.  In 
other  European  cities,  as  far  as  returns  are  available,  the 
collections  do  not  average  more  than  about  $1.50  per 
capita. 

In  Australia  the  collections  seem  to  be  nearly  up  to 
the  American  average.  But  little  fire  service  is  provided, 
but  the  population  supplied  is  scattered,  necessitating 
rather  great  length  of  distribution  piping.  The  per 
capita  quantities  of  water  supplied  are  not  high,  but  the 
cost  of  securing  the  water  is  relatively  high. 

In  arid  districts  the  per  capita  cost  of  water  works  may 
be  increased  almost  indefinitely  with  the  increase  in 
value  of  the  water  to  the  takers  and  in  the  cost  of 
securing  it. 

In  comparing  American  with  European  conditions,  it 
must  be  remembered  that,  in  general,  a  much  larger 
expenditure  has  been  made  in  Europe  for  the  purpose  of 
improving  the  quality  of  the  supplies,  and,  on  an  aver- 
age, the  qualities  of  the  waters  actually  supplied  show 
the  effect  of  this  expenditure  and  are  better  than  Ameri- 
can waters.  On  the  other  hand,  the  American  works 
have  been  built  at  considerable  additional  cost  to  enable 
them  to  supply  water  rapidly  in  case  of  fire,  a  condition 
which,  in  general,  does  not  exist  in  Europe  because  of 
the  less  inflammable  character  of  the  buildings;  and 


EUROPEAN  CONDITIONS.  169 

the  additional  cost  of  the  larger  pipes  and  reservoirs  to 
meet  this  condition  in  America  may  be  as  much  as  the 
additional  expenditures  for  quality  in  Europe. 

Labor  is  cheaper  in  Europe,  but  probably  the  number 
of  men  employed  is  enough  greater  to  offset  the  effect  of 
the  lower  wages  paid. 

The  principal  element  of  difference  is  in  the  quantity 
of  water  supplied.  American  cities  on  an  average  prob- 
ably use  two  or  three  times  as  much  water  per  capita  as 
European  cities,  or,  more  correctly,  they  waste  so  much 
as  to  produce  these  ratios  in  the  amounts  supplied.  It 
certainly  seems  reasonable  that  to  supply  two  or  three 
times  as  much  water  per  capita  the  cost  of  the  service 
would  be  increased  by  60  per  cent. 

The  disposition  of  the  $2.50  per  capita  collected  on  an 
average  in  America  is  about  as  follows :  First,  in  works 
where  the  supply  is  from  a  gravity  source,  and  no  purifi- 
cation is  used,  about  $0.50  per  capita  annually  is  used 
for  paying  the  general  expenses  of  administration,  of 
taking  care  of  services,  meters,  etc.,  of  making  repairs, 
and  of  maintaining  the  works  generally.  The  $2.00 
remaining  pays  4  per  cent  interest,  and  i  per  cent  depre- 
ciation, or  together  5  per  cent  capital  charges  on  a  cost 
or  value  of  works  averaging  $40  per  capita.  The  $40  is 
about  equally  divided  between  the  distribution  system, 
which  includes  the  pipes  in  the  streets  of  the  city,  the 
services,  meters,  etc.,  and  the  source  of  supply,  which 
includes  all  the  works  for  securing  the  water  and  bring- 
ing it  to  the  city. 

Second,  in  works  where  the  supply  is  pumped  from  a 
river  or  lake  near  at  hand,  with  or  without  purification, 


SOME  FINANCIAL  ASPECTS 

about  $0.50  is  used  for  the  general  expenses  as  above 
mentioned.  Another  $0.50  is  used  for  pumping  and 
purification  (rather  more  when  the  water  is  purified;  less 
when  it  is  not);  and  the  remaining  $1.50  pays  5  per  cent 
capital  charges  on  an  average  investment  of  $30  per 
capita,  of  which  $20  is  in  the  distribution  system  and  $10 
in  the  source  of  supply. 

Gravity  sources  of  supply  cost  more  to  secure,  but  are 
cheaper  to  operate. 

The  above  mentioned  figures  are  general  approxima- 
tions, given  to  show  general  water  works  conditions  in 
America  at  the  present  time,  but  wide  fluctuations  will 
be  found  in  individual  cases. 

Some  cities  are  so  located  that  no  good,  adequate 
source  of  supply  is  near  at  hand;  and  where  water  is 
brought  from  long  distances  and  is  pumped  and  purified, 
it  is  clear  that  it  cannot  be  delivered  at  the  cost  or  sold 
at  the  price  that  is  fair  for  a  water  drawn  from  a  pure 
and  ample  source  near  at  hand. 

Then  the  cost  of  distribution  differs.  In  a  city  on 
level  ground  where  one  service  or  one  system  of  pipes 
does  for  all,  the  cost  both  of  construction  and  of 
operation  is  less  than  on  a  hilly  site  where  separate 
high  service  districts  must  be  maintained,  involving 
additional  pipe  systems  and  additional  pumping  stations. 
And  a  city  that  is  compactly  built  up,  §o  that  it 
can  be  served  with  a  pipe  system  having  a  mile 
or  less  of  pipe  per  thousand  of  population,  can  be 
more  cheaply  served  than  a  scattered  city  with  long 
lines  of  pipe  running  out  where  there  are  but  few 
houses,  and  where,  taking  it  right  through,  two  or 


THE  VALUE   OF  PURE  WATER.  171 

even  three  miles  of  pipe  are  required  per  thousand  of 
population. 

Cities  that  waste  large  amounts  of  water  have  to  pay 
for  it.  The  cost  of  the  works  is  greater,  and  this  cost  is 
sure  to  be  represented  sooner  or  later  in  the  assessments. 

Matters  of  these  general  natures  largely  explain  why 
some  cities  can  be  supplied  for  less  than  $2  per  capita 
while  others  must  collect  over  $4  per  capita. 

The  service  of  water  is  one  of  the  cheapest.  The  aver- 
age American  family  pays  far  more  for  gas,  for  ice  and 
for  milk,  than  for  water.  In  my  own  household  in  New 
York,  taking  the  cost  of  Croton  water  at  $i,  the  average 
cost  of  other  household  supplies  is  as  follows:  Ice  $3, 
Light  $4,  Telephone  $5,  Coal  $13,  Milk  $15.  Taking 
into  account  the  nature  of  the  water  service,  which  has 
become  absolutely  indispensable,  the  low  cost  is  very 
remarkable. 

Rather  than  not  have  it,  a  city  like  New  York  could 
afford  to  pay  without  hesitation  ten  times  the  present 
water  rates;  and  such  rates  would  be  paid  if  there  was 
necessity  for  them,  as  happily  there  is  not,  and  never 
will  be. 

Some  interesting  computations  indicating  the  enor- 
mous value  of  pure  water  to  the  inhabitants  of  a  city  have 
been  recently  published.1  I  shall  not  repeat  them  here, 
but  will  only  call  attention  to  one  well  known  and  highly 
significant  fact.  When  the  inhabitants  of  an  American 
city  get  the  idea,  rightly  or  wrongly,  that  the  water  of  the 
public  service  is  not  good  to  drink,  many  of  them  pro- 
ceed to  supply  themselves  with  drinking  water  in  other 

1  The  Value  of  Pure  Water ;  G,  C,  Whipple  ;  John  Wiley  &  Son?. 


172  SOME  FINANCIAL  ASPECTS. 

ways.  Filters  of  greater  or  less  efficiency  are  installed 
in  thousands  of  houses,  and  bottled  spring  waters  find 
an  extended  sale  at  prices  which  represent  handsome 
profits  to  the  venders.  Such  sales  of  spring  water  may 
be  brought  about  by  the  turbidity  of  the  water,  or  by  its 
color,  or  by  tastes  and  odors,  or  by  iron  in  it,  or  by  de- 
ficiency in  hygienic  quality,  and  the  supposition,  often 
well  founded,  that  disease  may  be  produced  by  it. 

It  is  difficult  or  impossible  to  ascertain  even  approxi- 
mately how  much  money  is  spent  for  spring  water;  but 
in  some  cases  partial  returns  of  a  reliable  nature  indicate 
that  the  payments  for  spring  water  by  the  relatively 
small  number  of  people  who  can  afford  it,  are  equal  to 
twenty  per  cent  or  more  of  the  gross  revenue  of  the  water 
department.  This  ratio  of  expense  for  spring  water  prob- 
ably is  not  uncommon  in  American  cities,  and  there  are 
probably  some  cases  where  it  is  greatly  exceeded.  In 
the  homes  of  the  wealthy  the  spring  water  bill  may  be 
many  times  larger  than  the  charge  for  the  water  of  the 
public  supply. 

I  cite  this  condition  merely  to  show  the  value  which 
that  part  of  the  public  which  can  afford  it  puts  on  good 
water,  as  measured  by  its  willingness  to  pay  cash  for  it. 

Now  there  is  hardly  a  city  in  America  supplying  bad 
or  inferior  water  at  the  present  time  which  could  not 
substitute  a  new  supply,  or  purify  the  present  one,  no 
increase  of  quantity  being  made,  at  a  total  cost  repre- 
senting less  than  twenty  per  cent  of  the  water  rates;  and 
in  many  cases  this  could  be  accomplished  for  ten  per  cent 
of  those  rates,  or  even  less.  And  this  is  with  reference 
to  a  new  or  improved  supply  so  free  from  hygienic 


STANDARDS  OF  PURITY.  173 

objections,  turbidity,  color,  and  all  other  objectionable 
qualities,  that  there  would  be  no  reason  left  for  resorting 
to  spring  water. 

Such  a  standard  of  purity  is  clearly  within  the  reach 
of  all  cities  at  this  time.  There  is  no  good  reason 
why  a  lower  standard  in  any  particular  should  be 
accepted. 

And  in  many  of  our  cities  an  amount  of  money  suffi- 
cient to  bring  the  whole  public -supply  to  this  standard, 
if  it  were  so  applied,  is  spent  by  the  relatively  small  num- 
ber of  well-to-do  people  who  can,  or  think  they  must, 
afford  it  for  spring  water,  which  spring  water  is  not  of 
better  quality,  and  is  often  of  far  worse  quality,  than  that 
to  which  the  public  supply  for  all  the  people  might  rea- 
sonably be  brought. 

It  is  unnecessary  to  develop  this  matter  further. 
There  is  no  uncertainty  about  it.  Only  one  conclusion 
can  be  reached.  The  American  people  ought  to  have 
for  their  public  supplies  water  substantially  equal  in 
hygienic  quality  and  in  physical  appearance  and  attrac- 
tiveness to  the  best  spring  water.  Such  supplies  can  be 
secured.  Sometimes  water  of  this  quality  can  be  se- 
cured naturally;  at  other  times  by  artificial  purification. 
The  means  to  be  used  for  accomplishing  this  end  are  well 
known.  The  costs  of  carrying  them  out  are  reasonable. 
The  advantages  of  pure  water  are  worth  far  more  than 
the  cost  of  securing  it. 

The  service  of  water  to  the  public  as  the  business  is 
now  conducted  is  a  very  cheap  one.  The  people  could 
afford  if  necessary  to  pay  far  more  than  they  now  do 
for  good  water;  but  fortunately  in  most  cases  no  great 


174  SOME  FINANCIAL  ASPECTS. 

increase  in  the  cost  of  the  service  need  be  made  to 
secure  it. 

There  is  not  the  slightest  doubt  that  the  American 
people  will  more  readily  and  cheerfully  pay  $4  per  capita 
for  an  adequate  service  of  pure,  attractive  water  than 
they  will  pay  $2  for  an  inferior  service,  while  the  differ- 
ence in  cost  of  maintaining  the  service  will  never  be  as 
great  as  this. 

Under  these  conditions  the  plain  duty  of  the  water 
departments  and  of  the  water  companies  of  the  country 
is,  first,  to  provide  a  thoroughly  adequate  service  of  pure 
water  and  of  attractive  water;  and  second,  to  fix  the 
water  rates  so  that  this  service  can  be  paid  for  by  them. 

At  the  present  time  there  are  many  laws,  ordinances, 
debt  limits,  and  bonds  outstanding,  which  limit  action 
and  prevent  the  immediate  following  of  this  policy. 
But  where  there  is  a  general  determination  to  secure  a 
result,  it  can  be  reached,  and  a  better  understanding  of 
the  conditions  by  those  who  make  and  repeal  the  laws 
and  ordinances,  and  are  responsible  for  other  arrange- 
ments, is  the  first  step  in  bringing  about  the  desired 
conditions. 


CHAPTER   XVII. 

THE  LAYING  OUT  AND  CONSTRUCTION  OF 
WORKS. 

THE  amount  of  money  invested  in  water  works  in  the 
United  States  at  this  time,  1907,  is  probably  not  less  than 
$800,000,000,  and  the  true  value  of  the  properties  prob- 
ably exceeds  largely  this  figure.  The  amount  of  money 
spent  on  new  construction,  either  in  new  projects,  or  in 
the  development  and  enlargement  of  old  ones,  is  cer- 
tainly not  less  than  $30,000,000  per  year,  and  this  amount 
is  increasing. 

Of  this,  one-half  or  less  is  for  ordinary  extensions  of 
pipes,  for  installing  meters,  etc.,  and  the  rest  is  for  new 
sources  of  supply,  new  pumps,  and  new  purification 
works,  and  for  the  enlargement  of  old  ones. 

As  a  rule  men  do  that  best  which  they  are  accustomed 
to  do,  and  that  which  they  do  frequently;  they  do  less 
well  or  even  badly  the  things  that  they  have  not  done 
before.  It  looks  easy  enough  to  swim,  or  to  fit  a  coat, 
or  to  play  a  piano;  but  we  know  that  there  is  little  pros- 
pect of  success  in  doing  these  things  in  the  first  attempt 
of  the  novice, 

It  is  much  the  same  with  cities  in  the  building  of  water 
works.  The  work  that  is  done  frequently  and  regularly 
is  done  well,  often  extremely  well;  and  that  which  is 
undertaken  but  seldom,  or  for  the  first  time,  is  very  apt 


176      LAYING  OUT  AND  CONSTRUCTION  OF  WORKS. 

to  be  badly  managed;  and  many  misfit  coats  are  worn 
with  as  good  a  grace  as  possible  because  the  wearer  does 
not  wish  to  admit  that  he  did  not  know  how  to  cut  his 
own  coat.  It  may  even  be  that  he  does  not  yet  know  it 
to  be  a  misfit. 

Most  water  works  departments  lay  their  own  water 
pipes  and  services  and  set  their  own  meters.  That  is  to 
say,  they  do  these  things  with  their  own  men,  and  not  by 
contract.  As  a  rule  the  men  employed  are  honest,  intel- 
ligent and  faithful,  Practice  of  neighboring  cities  is 
studied  and  improvements  are  readily  adopted.  As 
a  rule  these  men  become  skilfull  as  well  as  faithful, 
and  their  work  is  well  done,  and  on  the  whole  it  is 
cheaply  done. 

The  work  done  in  this  way  represents  at  least  a  third 
of  the  whole  construction  account,  and  for  it  the 
departments  usually  secure  full  value  for  the  money 
expended. 

So  far  as  they  do  not,  it  is  mostly  due  to  failure  to  pro- 
vide and  work  to  a  sufficiently  comprehensive  general 
plan.  A  six-inch  pipe  is  put  down  this  year  in  a  street 
where  a  ten-inch  will  be  required  five  years  hence;  and 
when  this  happens  the  value  of  the  six-inch  first  laid  will 
have  largely  disappeared.  Such  losses  can  be  almost 
entirely  prevented  by  making  a  general  plan  of  pipes 
suitable  for  the  city  after  some  years  of  growth,  as  nearly 
as  that  growth  can  be  foreseen,  and  thereafter  laying  all 
pipe  in  accordance  with  it.  Much  money  can  be  saved 
in  that  way  in  comparison  with  that  which  is  spent  under 
the  too  common  system,  or  rather  lack  of  system,  where 
§uch  pipes  are  put  down  each  year  as  will  relieve  those 


WASTES  IN  CONSTRUCTION.  177 

deficiencies  of  the  system  which  then  appear  most 
pressing. 

But  the  wastes  from  badly  advised  piping  are  trifling 
when  compared  to  those  on  other  parts  of  the  construc- 
tion work.  This  is  because  the  departments  are  not 
used  to  laying  out  new  works  and  building  them.  These 
things  are  required  but  seldom  in  any  one  city,  and  those 
having  to  do  with  one  such  installation  are  seldom  on 
hand  for  the  work  of  building  the  next  one.  If  they 
were,  their  experience  in  many  ways  would  have  lost  its 
value,  owing  to  the  progress  of  the  art  in  the  interval. 

The  study  of  recent  works  of  neighboring  cities  is  often 
relied  upon,  and  if  rightly  used  it  is  most  helpful.  But 
occasionally  it  is  the  reverse,  where  local  conditions  do 
not  permit  of  copying.  Storage  reservoirs  are  built, 
where  the  need  is  rather  for  more  catchment  area  tribu- 
tary to  the  works;  large  distributing  reservoirs  are  built, 
where  smaller  ones  at  higher  levels,  or  more  pumps  or 
purification  works  would  be  far  more  useful;  and  types 
of  construction  useful  in  one  place  (or  not,  as  the  case 
may  be)  are  cheerfully  copied,  where  they  are  not  suit- 
able, and  where  the  money  could  be  better  laid  out  in 
other  constructions. 

Certainly  the  sources  of  supply  in  America,  taking  it 
right  through,  cost  a  fourth  more  than  they  would  cost 
if  the  methods  of  procedure  that  are  well  known  and 
tried  and  adapted  to  the  service  were  used  in  all  cases. 

Putting  it  in  another  way,  the  savings  that  could  be 
reasonably  made  in  water  works  construction  by  better 
management  and  by  better  engineering  certainly  amount 
to  several  millions  of  dollars  per  year  in  the  United 


178      LAYING  OUT  AND  CONSTRUCTION  OF  WORKS. 

States.  And  this  does  not  include  any  allowance  for 
savings  to  be  made  by  new  inventions  and  methods, 
which  would  largely  add  to  this  figure. 

These  possible  savings  represent  a  fund  that  may  be 
divided  between  the  people  (in  reduced  water  rates) 
and  the  engineers  and  superintendents  and  managers  (in 
increased  fees  and  salaries)  who  have  the  ability  to  bring 
the  improvements  about. 

The  public  does,  and  always  will,  get  most  of  the  sav- 
ings to  be  made  in  this  way;  but  there  is  plenty  of  chance 
for  men  of  ability  and  training  to  make  great  savings, 
and  to  receive  generous  compensation  for  doing  it,  and 
it  is  for  the  best  interests  of  all  that  such  services  should 
be  secured  by  the  water  departments  and  be  adequately 
paid  for  by  them. 

Some  cities  and  water  companies  have  for  many 
years  made  special  efforts  to  secure  such  services,  and 
the  superior  character  of  their  works,  and  the  increased 
values  which  they  have  obtained  for  their  expenditures, 
are  very  clear  to  the  few  who  take  the  trouble  to  inquire 
carefully  into  these  matters. 

On  the  other  hand,  some  of  our  largest  cities  spend 
fifty  per  cent  more  on  their  works  than  is  necessary,  and 
sometimes  even  a  hundred  per  cent  more.  Some  do 
even  worse  than  this.  They  build  expensive  works  that 
on  any  rational  theory  of  development  they  do  not  want, 
and  cannot  use  to  advantage. 

Some  of  this  is  due  to  incompetent  engineering  advice. 
More  of  it  is  due  to  lack  of  advice  or  to  failure  to  act 
upon  it  when  it  is  obtained. 

There  is  much  more  that  might  be  written  upon  this 


UNNECESSARY  EXPENDITURES.  179 

subject.  It  might  be  shown  how  in  some  lines  of  work 
the  development  is  so  rapid  that  even  the  most  recent 
text-books  are  hopelessly  out  of  date;  how  the  subjects 
are  becoming  so  complex  that  only  the  principles  and  not 
the  important  details  can  be  treated  in  them;  how  the 
most  efficient  works  are  designed  by  groups  of  men,  each 
attending  to  the  parts  which  he  best  understands,  and  all 
under  the  general  direction  of  a  chief  who  has  a  clear 
idea  of  the  end  to  be  reached  and  the  way  of  reaching 
it,  though  he  may  know  less  of  many  of  the  details  than 
his  subordinates;  how  the  only  way  to  learn  a  business  is 
to  be  brought  up  in  it,  and  how  it  cannot  be  learned  by 
a  casual  inspection  from  the  outside. 

There  is  a  strong  temptation  to  develop  some  of  these 
ideas,  but  it  must  not  be  done  in  this  place.  The  writer 
is  too  directly  interested  in  this  business.  To  take  up 
these  matters  would  be  too  much  like  blowing  his  own 
horn,  or  at  best,  that  of  his  profession.  And  besides, 
the  water  departments  are  steadily  finding  out  the  truth 
about  these  matters,  and  it  is  better  that  they  should 
reach  it  in  their  own  way. 

At  this  point  I  wish  to  record  a  tribute  to  the  many 
faithful,  earnest,  unpaid,  or  but  slightly  paid,  men  serv- 
ing on  water  boards,  and  water  committees,  who  have 
conscientiously  studied  the  water  problems  of  their  cities 
and  the  best  ways  of  solving  them,  and  have  stood  for 
the  right,  even  against  strong  but  ignorant,  or  misin- 
formed public  opinion,  and  have  in  this  way  secured  for 
the  cities  which  they  have  served  water  supplies  far  better 
than  would  otherwise  have  been  possible.  I  have  known 
hundreds  of  these  men,  working  year  after  year  for  the 


l8o      LAYING  OUT  AND  CONSTRUCTION  OF  WORKS. 

good  of  their  cities,  entirely  without  compensation,  and 
too  often  without  thanks.  Sometimes  I  have  had  an  in- 
sight into  what  effort  it  has  cost  them.  More  often  I 
have  realized  in  some  measure  the  value  of  their  services 
to  the  communities  in  which  they  live. 

It  is  this  feature  of  our  municipal  life,  too  often  for- 
gotten or  unknown,  which  must  increase,  as  I  believe  it 
will,  until  it  controls  and  excludes  the  baser  elements. 
All  honor  to  the  men  who  quietly  and  without  show  do 
their  full  duty  in  the  public  service  1 

The  water  works  superintendents  also  deserve  a  word, 
for  they  are  among  the  hardest  working  and  most  poorly 
paid  of  men.  With  telephones  in  their  residences  they 
are  on  duty  twenty  four  hours  a  day  and  seven  days  in 
the  week.  Vacations  are  few  and  short.  All  routine 
work  usually  goes  through  their  hands,  and  very  often, 
when  they  are  stronger  and  better  informed  than  their 
boards  or  committees,  they  practically  determine  the 
policy  to  be  followed  on  all  important  matters.  And,  as 
a  rule,  the  superintendents  are  right.  As  a  rule  they  are 
not  men  of  broad  training,  and  often  they  miss  the  main 
chance,  but  on  the  whole,  things  are  far  more  apt  to  go 
right  when  the  superintendent's  suggestions  are  followed, 
as  they  are  pretty  apt  to  be.  Considering  the  conditions 
of  service,  it  is  surprising  that  the  superintendents,  as  a 
class,  are  as  efficient  as  they  certainly  are. 

For  the  future  it  is  to  be  hoped  that  the  business  will 
be  made  more  of  a  profession;  that  the  salaries  paid  will 
be  larger;  and  that  more  men  of  broad  technical  training 
will  be  enlisted  in  the  service. 


CHAPTER   XVIII. 

ON    THE    FINANCIAL    MANAGEMENT    OF    PUBLICLY 
OWNED    WATER    WORKS. 

UNDER  this  heading  I  shall  not  attempt  to  describe  the 
methods  in  actual  use  in  American  cities  for  financing 
their  publicly  owned  water  works.  These  methods  are  cer- 
tainly varied  and  in  many  cases  have  admirable  features. 
I  propose  here  to  bring  together  those  methods  and  ar- 
rangements which  seem  particularly  suitable,  and  then 
to  make  a  financial  scheme,  ideal  and  visionary,  to  the 
extent  that  no  city  is  following  it  throughout,  but  practical 
and  tried,  to  the  extent  that  most  of  its  individual  features 
are  in  successful  use  in  one  or  another  American  city. 

Likewise  no  treatment  of  the  management  of  works  by 
private  companies  is  intended,  though  the  plan  outlined 
for  city  management  follows  closely,  as  it  should,  the 
arrangements  that  are  suited  to  company  management, 
with  only  one  important  point  of  difference :  That  is,  that 
a  company  has  properly  for  its  end  the  payment  of  divi- 
dends, while  the  object  of  publicly  owned  works  is  to 
give  as  good  service  as  possible,  and  to  assess  the  cost  of 
it  as  fairly  as  it  can  be  done,  both  between  the  different 
takers  at  the  present  time,  and  between  those  of  to-day 
and  those  of  the  years  that  are  to  come,  during  the  period 
for  which  financial  arrangements  now  made  will  be  in 
operation. 

181 


182  FINANCIAL  MANAGEMENT. 

The  method  to  be  here  outlined  is  intended  to  secure 
this  result  as  fairly  as  possible  and  with  a  minimum  of 
trouble  and  inconvenience.  It  is  more  complicated  than 
the  methods  now  used  by  many  water  departments,  but 
perhaps  not  more  eleborate  than  is  necessary  to  reach  the 
desired  results.  For  the  methods  of  bookkeeping  used  by 
many  water  departments  do  not  give  a  clear  idea  of  their 
financial  situation  nor  whether  the  present  arrangements 
are  leading  to  bankruptcy  or  to  an  unusually  large 
surplus,  unless  the  tendency  is  very  strong. 

This  is  often  the  case.  Water  departments  collect 
more  than  is  really  needed,  because  of  ignorance  as  to 
true  conditions;  but  this  tends  to  good  service,  and  at 
worst  only  means  that  the  present  generation  is  paying 
the  water  bills  of  a  future  one  in  some  measure.  The 
opposite  condition  of  too  low  collections  is  fortunately 
less  common,  though  it  has  been  followed  by  many  cities. 
In  the  end  it  is  far  more  disastrous  to  have  the  rates  too 
low  than  too  high. 

In  developing  this  proposed  method  a  number  of 
definitions  will  be  necessary. 

The  True  Value  of  a  water  works  property  as  a  whole 
is  the  fair  market  value  of  the  property,  including  all  real 
estate,  rights  of  every  kind,  and  structures,  valued  as  if 
the  present  owners  wished  to  sell,  and  as  if  a  party  at 
hand  was  desirous  of  buying  and  operating  it.  The  case 
of  the  transfer  of  the  works  from  private  to  public  owner- 
ship may  be  assumed  as  the  one  for  which  there  are  most 
precedents,  but  transfer  from  one  company  to  another, 
and  from  the  city  to  a  company  may  also  be  consid- 
ered. 


VALUE  OF  WORKS.  183 

In  general,  it  will  be  fair  to  assume  that  the  franchise  has 
expired  and  that  no  special  allowance  is  to  be  made  for 
it,  though  in  some  cases,  as  when  a  city  has  just  con- 
demned works  with  a  valuable  franchise  for  which  it  has 
paid,  this  would  be  unfair  and  the  franchise  value  should 
be  included.  A  going  concern  value,  or  a  value  for  the 
fact  of  having  actual  connections  and  an  established 
business,  in  comparison  with  a  plant  otherwise  complete, 
but  with  a  business  yet  to  be  acquired,  may  fairly  be 
allowed. 

The  Appraised  Value  is  an  approximation  to  the  true 
value,  made  at  a  given  time  by  the  water  department,  or 
for  it,  to  be  used  as  a  basis  of  calculation.  The  methods 
of  appraisal  of  water  works  properties  need  not  be  dis- 
cussed here.  Such  properties  are  frequently  valued  by 
arbitration,  or  by  court  proceedings,  for  the  purpose  of 
fixing  the  sale  value  from  a  company  to  a  city,  or  else  for 
the  purpose  of  serving  as  a  basis  for  fixing  the  water  rates 
which  may  be  charged  by  a  company.  The  principles 
of  water  works  valuation  have  been  ably  discussed,  and 
many  lawyers  and  engineers  have  had  extended  experi- 
ence in  their  application. 

The  Book  Value  or  capital  account  is  the  value  of  the 
plant  as  a  whole  as  used  for  the  purpose  of  bookkeeping 
and  computation.  It  may  be  arrived  at  in  a  number  of 
ways,  but  most  frequently  by  taking  the  book  value  of 
the  preceding  statement  and  adding  to  it  all  moneys  spent 
since  on  construction,  and  substracting  all  allowances 
to  be  made  for  depreciation.  The  book  value  is  to  be 
kept  as  nearly  as  may  be  to  the  appraised  value.  This 
can  be  controlled  by  the  amount  marked  off  for  depre- 


184  FINANCIAL  MANAGEMENT. 

elation,  and  the  depreciation  should  be  adjusted  to  a 
simple  schedule,  to  produce  the  required  result  as  nearly 
as  can  be  estimated.  New  appraisals  may  be  made 
once  in  five  or  ten  years,  and  the  depreciation  allowance 
increased  or  decreased  as  necessary  to  preserve  an  ap- 
proximate equality. 

The  Bonded  Indebtedness  is  the  whole  outstanding 
bonded  obligation,  less  the  sinking  fund  if  there  is  one. 
Water  works  are  generally  paid  for  by  cities  in  the  first 
place  by  money  raised  on  bond  issues,  and  if  the  value 
equals  the  cost  when  first  built,  then  the  bonded  indebt- 
edness equals  the  value  of  the  plant.  But  such  a  condi- 
tion does  not  last.  Usually  with  plants  long  in  operation, 
and  bonds  partially  paid  off,  the  bonded  indebtedness  is 
far  below  the  fair  value  of  the  property. 

The  City's  Equity  is  the  book  value  of  the  plant,  less 
the  bonded  indebtedness.  This  corresponds  to  the 
stock  value  of  a  plant  owned  by  a  company.  This 
equity  I  would  treat  exactly  as  if  it  were  stock.  Its 
ownership,  vested  in  the  city  government  as  trustee  for 
the  citizens,  gives  the  right  to  control  the  works,  and  a 
fair  rate  of  dividends  on  its  value  should  normally  be 
earned  by  the  operation  of  the  plant. 

The  Construction  Account  must  be  rigidly  separated 
from  the  operation  account,  and  must  show  all  money 
spent  for  new  works  and  for  additions. 

The  Operation  Account  must  include  all  receipts  and 
expenses  in  the  normal  operation  of  the  works,  includ- 
ing all  interest  payment  on  the  bonds,  and  all  other  pay- 
ments in  the  way  of  returns  on  the  invested  capital, 
and  the  allowance  for  depreciation. 


OPERATING  ACCOUNT.  185 

The  principal  items  that  will  go  to  make  up  the  opera- 
tion account  are  as  follows: 

Receipts',  (i)  the  water  receipts  from  all  private 
consumers.  This  is  the  principal  part  of  the  income, 
and  the  methods  of  collecting  it  now  in  use  are  usually 
good  and  adequate. 

(2)  Receipts  for  water  supplied  to  other  city  depart- 
ments. The  bills  for  such  ser vices  should  rest  on  meter 
measurement,  should  be  made  up  at  the  same  rates  as 
would  be  charged  to  private  takers  for  the  same  services, 
and  should  be  promptly  collected  in  all  cases;  and  other 
city  departments  using  water  should  be  authorized  and 
required  to  pay  for  it  out  of  their  appropriations,  and 
when  necessary  those  appropriations  should  be  increased 
to  cover  this  item.  Only  a  few  American  cities  have 
followed  this  practice.  Most  of  them  have  supplied 
water  without  charge  to  other  city  departments.  And 
the  water  departments  have  had  to  pay  dearly  for  this 
generosity.  For  other  city  departments  receiving  water 
without  cost  and  without  limit  are  the  most  incorrigible 
wasters  of  water.  The  loss  of  water,  which  is  equivalent 
to  loss  of  revenue,  and  to  increased  operating  expenses 
to  keep  up  the  supply,  is  a  direct  hardship  on  the  water 
departments.  Further,  the  loss  is  not  limited  to  the 
direct  loss.  The  example  of  public  waste  of  water  is 
irreconcilable  with  demands  for  private  suppression  of 
waste,  and  the  public  is  not  slow  to  see  the  point  and  act 
on  it. 

The  only  adequate  way  to  stop  this  abuse  is  to  meter 
the  water  to  each  department  and  collect  for  it  at  current 
rates  from  the  appropriations  for  that  department. 


186  FINANCIAL  MANAGEMENT. 

It  need  only  be  suggested  that  no  successful  com- 
mercial or  manufacturing  business  is  operated  without 
making  charges  between  different  stores,  factories  and 
departments,  and  the  necessity  for  such  charges  is  cer- 
tainly not  less  in  city  business. 

(3)  A  collection  from  the  city  for  hydrants  and  water 
for  fire  protection.  Private  water  companies  always 
charge  for  this  service.  Some  publicly  owned  works 
also  charge  for  it,  but  most  of  them  do  not.  The  charge 
should  be  made  in  all  cases,  but  the  rate  of  charge  may 
be  fixed  at  as  low  a  figure  as  will  cover  the  additional 
expense  of  maintaining  hydrants,  and  the  excess  capaci- 
ties of  the  pipes  needed  to  make  them  effective.  It  is 
impossible  to  make  a  close  computation  of  the  fair 
charge  for  this  service,  but  a  reasonable  approximation 
may  be  reached. 

The  rate  of  charge  might  appropriately  be  higher 
where  a  pressure  sufficient  to  give  fire  streams  direct 
from  the  hydrants  is  maintained,  that  is  to  say  for  hy- 
drant pressures  of  seventy  pounds  and  over;  and  lower 
where  the  pressure  is  so  low  as  to  be  only  effective  when 
increased  by  the  use  of  steam  fire  engines. 

There  will  be  some  minor  collections,  but  substantially 
these  three  items  will  make  up  the  gross  revenue,  and 
the  rates  charged  must  be  adjusted  from  time  to  time 
to  produce  the  required  income. 

The  payment  side  of  the  operating  account  will  be 
made  up  principally  of  these  five  items: 

(i)  Operating  expenses,  including  all  salaries,  general 
expenses,  costs  of  pumping,  protecting  catchment  areas, 
maintaining  mains,  services  and  meters,  special  engi- 


OPERATING  ACCOUNT.  187 

neering  and  other  professional  advice,  and,  in  short,  all 
current  expenses  of  every  sort. 

Space  in  city  buildings  not  owned  by  the  water  depart- 
ment should  be  paid  for  at  current  rates  for  rent,  and 
all  services  rendered  by  other  city  departments  should 
be  paid  for,  and  the  amounts  included  under  this 
heading. 

(2)  Interest  on  all  bonds  outstanding.     Usually  there 
is  no  indebtedness  outside  of  the  bonds  issued  for  con- 
struction, but  if  there  is  any  other  the  interest  payments 
upon  it  should  be  included  in  this  item. 

(3)  Taxes  on  the  works,  assessed  precisely  as  if  the 
works  belonged  to  a  private  company.     Water  works  at 
present  pay  taxes  on  those  .parts  of  their  works  located 
outside  the  city  limits  to  those  towns,  etc.,  in  which  they 
are  located,  but  often  under  special  rules  of  assessment 
made  by  the  state  legislatures,  limiting  the  assessments 
to  sums  far  below  the  full  values  of  the  properties.     Hoi- 
yoke  has  set  the  admirable  example  of  taxing  also  the 
parts  of  the  works  in  the  city  on  the  same  basis  as  other 
property,  and  this  example  is  worthy  of  being  invariably 
followed.     The  basis  of  assessment  should  be  as  nearly 
as  possible  that  followed  on  private  property.     There 
should  be  no  attempt  to  unduly  reduce  the  assessment. 
There  is  enough  tax  dodging,  and  the  city  which  suffers 
from  it  should  set  a  good  example. 

The  reasons  for  leaving  many  forms  of  city  property 
without  taxation  do  not  apply  to  water  works  property. 
It  is  commercial  and  profitable  property,  and  is  no  less  so 
because  it  belongs  to  the  city,  and  it  should  be  treated 
accordingly.  School  and  university  property  is  usually 


1 88  FINANCIAL  MANAGEMENT. 

exempt  from  taxation  as  long  as  used  directly  for  educa- 
tional purposes;  but  as  soon  as  a  revenue  is  derived  from 
any  part  of  it  (even  though  thit  revenue  is  used  for  edu- 
cational purposes)  that  part  becomes  taxable.  This  rule 
is  just,  and  it  should  be  applied  to  water  works  property. 

(4)  A  group  of  charges,  calculated  on  different  theo- 
ries, but  all  serving  the  same  general  purpose,  including 
sinking  fund  payments,  depreciation  allowances  marked 
off  from  the  capital  account  and  charged  to  the  operating 
account  at  the  end  of  the  year,  and  all  payments  for 
renewals  except  minor  renewals,  paid  out  of  operating 
expenses. 

The  amount  to  be  paid  into  sinking  funds  is  often 
established  by  law  or  by  the  provisions  of  the  bonds ;  the 
amount  paid  for  renewals  is  easily  ascertained;  but  the 
amount  allowed  for  depreciation  is  a  far  more  difficult 
matter  to  arrive  at.  Its  regulation  ultimately  depends 
upon  the  principle  that  it  is  to  suffice  to  keep  the  book 
value  and  the  true  value  as  near  together  as  possible,  and 
time  only  will  show  whether  the  amounts  assumed  and 
used  are  adequate.  In  the  meantime  an  approximation 
must  be  made  and  used,  and  modified  whenever  the 
experience  already  accumulated  shows  clearly  that  the 
charges  that  have  been  used  are  either  too  high  or  too 
low.  At  the  outset  it  is  better  to  allow  too  much  for 
depreciation  than  too  little. 

When  the  whole  cost  of  the  works  is  represented  by 
outstanding  bonds,  on  which  sinking  fund  payments  are 
established,  such  payments  alone  may  be  sufficient  or 
even  excessive,  and  no  further  depreciation  allowance 
need  be  made. 


DEPRECIATION  ALLOWANCE.  189 

The  allowance  also  may  properly  be  less  as  more 
extensive  and  thorough  renewals  are  made,  thus  keeping 
up  the  value  of  the  property. 

A  general  increase  in  the  value  of  real  estate  and  of 
the  cost  of  building  will  make  the  works  more  valuable 
and  reduce  temporarily  the  need  for  a  depreciation  allow- 
ance, while  the  reverse  condition  will  increase  it.  The 
allowance  will  also  be  less  where  the  works  are  designed 
wisely  with  reference  to  future  growth,  so  that  but  little 
will  have  to  be  discarded  as  the  years  go  by,  and  as  all 
parts  of  the  plant  are  carefully  looked  after  and  protected. 
The  care  of  the  mains  to  prevent  deterioration  resulting 
from  stray  currents  of  electricity  from  trolley-cars  (called 
electrolysis),  for  instance,  would  tend  to  reduce  deprecia- 
tion, and  lack  of  attention  to  it  might  greatly  increase  it. 

It  is  apparent  that  anything  like  a  close  computation  is 
impossible.  It  is  my  feeling,  based  on  the  examination 
of  a  number  of  old  works,  and  on  estimates  and  compu- 
tations relating  thereto,  that  for  most  American  water 
works  an  annual  allowance  of  one  per  cent  of  the  value 
of  the  property  for  all  the  charges  coming  under  this 
item  will  suffice. 

In  some  cases  half  this  charge  would  no  doubt  suffice. 
With  increasing  values  of  real  estate  some  works  would 
stand  no  allowance  at  all  for  a  time,  but  this  should  never 
be  taken  as  a  permanent  basis.  On  the  other  hand, 
with  badly  designed  works,  or  with  sources  of  supply 
near  the  limit  of  their  usefulness,  either  because  of  in- 
sufficient quantity  or  unsatisfactory  quality,  so  that  the 
early  abandonment  of  parts  of  the  works  must  be  con- 
templated, charges  of  two  or  three  per  cent,  or  more, 


190  FINANCIAL  MANAGEMENT. 

might  be  required  until  a  better  and  more  permanent 
basis  was  reached. 

(5)  The  payment  of  dividends  on  the  stock,  or  on 
the  city's  equity  in  the  property.  The  practical  opera- 
tion of  the  water  works  in  New  York,  Philadelphia, 
Pittsburgh,  and  many  other  cities,  results  in  the  realiza- 
tion by  the  city  of  a  certain  return  (and  often  a  large  one) 
on  its  investment  in  the  works,  but  in  no  case  is  such 
a  plan  systematically  and  adequately  carried  out.  In 
many  cities  the  opposite  principle  is  followed.  The 
city's  equity  in  the  works  is  deliberately  overlooked) 
and  no  payments  are  made  on  account  of  it. 

The  city's  equity  may  be  the  result  either  of  money 
raised  by  taxation  and  invested  in  the  works,  or  of  sur- 
plus profits  from  operation,  which  have  been  accumu- 
lated by  the  department.  In  the  former  case  there 
can  be  no  possible  reason  why  the  city  should  not 
receive  a  reasonable  return  on  its  investment.  In  the 
latter  case  it  may  be  urged  that  as  the  accumulation  is 
made  up  of  water  profits  it  should  be  used  for  the  benefit 
of  water  takers ;  or,  in  other  wrords,  it  is  held  that  water 
should  now  be  sold  for  less  than  actual  cost  because  in 
the  early  years  of  operation  it  was  sold  for  more  than 
cost,  and  it  is  held  that  the  accumulation  from  the  profits 
of  the  early  sales  must  be  dispersed,  and  lost  to  the  city. 

The  writer  believes  that  it  is  fairer  and  more  business- 
like to  regard  the  past  as  a  closed  chapter;  to  take  mat- 
ters as  they  stand;  to  find  out  the  true  cost  of  supplying 
water  under  present  conditions  as  nearly  as  it  can  be 
ascertained,  that  cost  including  interest  on  all  the  money 
invested  in  or  represented  by  the  present  value  of  the 


AS  TO  THE  PROFITS.  191 

plant,  regardless  of  whether  the  equity  now  owned  by 
the  city  has  been  produced  by  money  raised  by  taxation 
or  from  surplus  profits  of  the  works  themselves. 

The  management  of  the  matter  by  the  city  may  follow 
that  which  would  be  followed  by  an  individual  in  man- 
aging a  company  for  the  benefit  of  the  stock  which  he 
owned  in  it,  with  only  this  limit,  that  it  may  be  supposed 
that  the  city  only  cares  to  make  a  moderate  dividend 
rate,  and  will  reduce  the  water  rates  whenever  it  can  do 
so  without  reducing  the  dividend  rate  too  low.  In  years 
of  bad  business  it  will  reduce  dividends  or  pass  them. 
With  good  business,  fair  dividends  will  be  paid,  and  the 
average  dividend  through  a  term  of  years  may  reason- 
ably be  kept  somewhat  greater  than  the  rate  of  interest 
which  is  paid  on  the  bonded  indebtedness.  The  extra 
rate  is  to  cover  the  element  of  risk  in  the  business,  and. 
corresponds  to  the  extra  rate  that  there  must  be  a  chance 
of  earning  to  make  such  a  business  attractive  to  a 
private  investor. 

As  to  the  disposition  of  the  dividends  received  by 
the  city,  the  first  use  would  be  naturally  to  take  up  new 
stock  to  pay  for  additions  to  the  works.  It  is  clearly 
wise  to  do  this,  and  the  money  so  contributed  for  con- 
struction purposes  would  render  unnecessary  a  corre- 
sponding amount  of  bonds.  And  this  policy  would 
increase  the  profits  to  the  city  from  the  business  as  its 
equity  in  the  works  increased. 

In  rapidly  growing  works,  and  where  the  city's  equity 
at  first  was  small,  all  dividends  for  many  years  could  be 
wisely  reinvested  in  the  works;  but  ultimately  a  large 
net  revenue  to  the  city  above  the  requirements  for  new 


FINANCIAL  MANAGEMENT. 


construction  would  result  from  this  policy,  and  this 
revenue  might  be  dedicated,  if  desired,  to  providing 
libraries  and  hospitals  and  parks,  or  any  other  public 
works  not  of  a  productive  nature. 

The  general  policy  thus  outlined,  if  adopted,  would 
place  publicly  owned  works  on  the  basis  of  privately 
owned  works  in  all  respects  but  two;  namely,  th?  interest, 
apart  from  dividends,  in  giving  the  best  possible  service, 
and  the  absence  of  desire  to  earn  more  than  a  fair  rate  of 
interest  on  the  capital  invested.  And  these  two  reasons 
are  precisely  the  reasons  for  public  ownership,  and  they 
are  substantially  the  only  reasons  for  it.  In  all  other 
respects  the  management  should  be  the  same  in  both  cases. 
The  publicly  owned  works  should  have  the  benefit  of  all 
the  collections  that  a  company  could  make  in  its  place, 
and  it  should  be  subject  to  all  the  charges  that  a  company 
would  have  to  pay. 

The  comparison  with  a  company  is  convenient  and 
helpful,  but  the  real  reason  for  the  adoption  of  these 
methods  is  not  that  they  are  used  by  companies,  but 
because  they  are  sound  business,  and  would  be  equally 
desirable  if  there  were  not  a  water  company  in  existence. 

Their  use  will  lead  to  the  sale  of  water  to  everyone  at 
actual  cost,  as  nearly  as  that  cost  can  be  determined,  and 
no  one  ought  to  expect  to  get  water  cheaper;  and  it  will 
result  ultimately  in  the  ownership  by  our  cities  of  splendid, 
safe,  revenue-producing  properties. 

And  the  ownership  of  such  properties  will  be  doubly 
gratifying  when  they  supply  clean  water. 


INDEX. 


PAGE 

Aerating  devices 97 

Aeration  to  remove  tastes  and  odors 109 

Boston  water  works. . 5 

Catchment  areas,  care  of n 

population  upon 12 

Catskill  supply  for  New  York  City 4 

Chlorine  liquid  as  a  disinfectant 107 

Clean  water,  value  of 171 

Coagulating  basins 97 

devices 96 

effect  of  upon  red  water 72 

Color,  fermentation  of 116 

in  river  waters 39 

in  water,  of  impounding  reservoirs 24 

removal  of 114 

Consumption  per  capita  in  certain  cities 151 

Copper  sulphate,  use  of 23 

Covered  reservoirs 132 

Croton  water  works i 

Disinfectant,  liquid  chlorine 107 

ozone 107 

ultra-violet  rays 107 

Disinfection 100 

clean  water  necessary  for 108 

in  connection  with  filtration 105 

Filtered  water,  storage  of 132 

Filters,  required  size  of 135 

193 


194  INDEX. 

PAGE 

Financial  aspects 167 

management  of  water  works 181 

Fire  risk,  great  in  American  cities 149 

service 143 

special  high  pressure 148 

Great  Lakes,  water  supplies  from 29 

Ground  water  from  limestone 48 

from  sand  and  gravel 43 

from  sandstone  rock 46 

hardness  of 50 

iron  in 52 

manganese  in 55 

supplies 42 

supplies,  sea  water  in 56 

Hardness  of  ground  water 50 

removal  of 1 23 

Hygienic  standards 128 

Hypochlorite  of  lime  as  a  disinfectant 102 

Impounding  reservoirs. 2 

color  of  water  in , . . .  24 

fermentation  of  color  in 116 

stagnation  of  water  in 14 

stripping 21 

use  of  copper  sulphate  in 23 

Intermittent  filtration 112 

Iron  in  ground  water 52 

in  water  from  service  pipes 67 

removal  of 124 

pipes,  effect  of  upon  quality  of  water 59 

tuberculation  of 59 

Lawrence  experiment  station 76 

filters 76 

Laying  out  water  works 176 

Louisville  experiments 78 

Limestone,  ground  water  from 48 


INDEX.  195 

PAGE 

Manganese  in  ground  water 55 

Mechanical  filters 94 

early 75 

list  of 86 

Mechanical  filtration  to  remove  tastes  and  odors no 

Meter  rates,  basis  for 154 

low  rates  objectionable 164 

service  charge 158 

sliding  scale 163 

Meters 154 

Micro-organisms,  in  water 18 

New  York  City  water  works i 

Ozone  as  a  disinfectant 101-107 

Peak  load,  provision  for 136 

Population  upon  various  catchment  areas 12 

Pressure  required  in  water  works 141 

reason  for  higher 142 

Purifying  water,  classification  of  methods  of 89 

Red  water 67 

Relative  cost  of  water 171 

River  supplies,  sanitary  aspects  of 33 

waters,  color  in 39 

turbidity  in 37 

Rivers,  water  supply  from 32 

Sand  and  gravel,  water  from 43 

filters 95 

early 74 

list  of 88 

filtration  to  remove  tastes  and  odors in 

Sandstone,  ground  water  from 46 

Sanitary  inspection 13 

Scrubbers 93 

Sea  water  in  ground  water  supplies 56 

Sedimentation 93 


196  INDEX. 

PAGE 

Service  charge 158 

pipes,  effect  of  water  upon 67 

Sewage  pollution,  removal  of  effects 125 

purification , .     34 

Small  lakes,  water  supplies  from 26 

Softening 81-1 23 

Stagnation  of  water  in  impounding  reservoirs 14 

Storage,  amount  required 9 

large  amount  required  in  dry  climates 8 

of  filtered  water 132 

Straining 92 

Stripping,  impounding  reservoirs 21 

Tastes  and  odors 80-8  r 

from  organisms 1 8 

from  stagnation 17 

in  reservoir  waters 17 

intermittent  filtration  to  remove 112 

mechanical  filtration  to  remove no 

methods  of  removing 109 

sand  filtration  to  remove in 

Tuberculation  of  iron  pipes 59 

Turbidity,  in  river  waters 37 

removal  of 119 

Ultra-violet  rays,  for  disinfection 107 

Use  and  waste  of  water 151 

Value  of  clean  water 171 

Water  purification,  history  of,  in  America 73 

Water,  use  and  waste  of 151 

Water  works,  amount  of  money  invested  in 175 

financial  management  of 181 

required  size  of 134 


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OF   THE 

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22 


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